Hold the Flood — Design Document

DES102 | draft r2 | 2026-09-06 | Lead Game and Systems Designer | In review

This is a proposal for a game, written before anything has been built. It follows the direction PM selected for drafting (A, "The Borrowed Route") and PM's six required corrections. Nothing in it is owner-approved, nothing has been played, and every number is a starting guess to be tested later. The enemies, the setting, the small colony and the modest equipment growth are all proposals for the owner to judge. Bookkeeping, revision codes and the answer-by-answer map to reviewers' findings are in Appendix B; the body is written to be read on its own. Terms are explained at first use and collected in Appendix A.

1. The pitch

You are a surveyor for a dozen survivors living on one dock above a drowned district. Below you is a flooded pumping station whose machinery still runs, and a mass of hostile bioelectric organisms, the Flood, that pours in on a schedule. You cannot kill the Flood. You can learn the district well enough to be where it is not, and to make it go where you want.

The whole district runs on one rule: current. Current flows through touching metal and through water to everything the water connects. Current opens doors, lights lamps, and calls the Flood, because the Flood follows lit beacons. Current is also how your gear works, how your backpack is packed, and what keeps the colony's dock dry. Every discovery you make is a new consequence of that one rule, and every experiment is a bet about what the current will do.

Each expedition is about fifteen minutes. Three surges of the Flood arrive, each larger, each announced in advance. Between them you explore, gather salvage, and run experiments. You leave by a dock before the third surge closes the district, or you are rescued without your cargo. What you learn stays with you. What you carried out repairs the colony. Then you go back down, knowing more.

Why this game exists. Survival games with automatic weapons and rising crowds are good at pressure and bad at curiosity: there is never a reason to stop and look. This design makes the pressure legible, so you can compute when you are safe, and makes every safe minute worth spending on understanding, because understanding is what changes where the pressure lands. The Flood is not something you beat. It is something you learn to route.

What the rule does that its inspirations do not. Water carrying current is not a new idea; the owner's own reference games use it, and one of them sits on a simulation of every pixel so that the same rule produces chaos for hundreds of hours. This design deliberately does not simulate; its channels are wet or dry. What it does instead, and what the reference games do not, is make one rule answer four questions at once: what fights, what opens, where the enemy mass goes next, and how your own gear is packed, with the colony's dock as the fifth. The value is not surprise from chaos; it is consequence you can compute, so that a plan is possible and a mistake is legible. A player who has seen "wet channel plus coil equals stun" has not seen the mechanic; they have seen one of its four faces, and the game is about noticing that the other three are the same face.

Who this is for, and what it sits beside. Proposed audience: players of automatic-weapon crowd games who want to think, and players of exploration mysteries who will accept pressure as the price of a puzzle worth solving. It sits beside the owner's named inspirations rather than against them: nearer to the resource-gathering crowd game in moment-to-moment feel, nearer to the room-by-room mystery in what keeps you coming back, and unlike the grid-inventory games in that the pack is small on purpose. No market claim is made here; audience, price and comparables are not yet among the document criteria, and section 17 asks the owner to treat them as decisions.

A two-minute example

You are in the yard, a salvage-strewn courtyard beside a shallow channel, and you have found a sealed hatch into the pump hall. A cable runs from the hatch along the channel to a dark lamp on a post: the yard's beacon. Your forecast display says the next surge arrives in ninety seconds, through the causeway on the far side of the district, because the causeway's beacon is the one that is lit. The hatch is sealed because the yard has no power.

There is a switch at the head of the causeway that decides which side of the district gets power. If you run to it and throw it to the yard, the hatch will open and stay open. The yard beacon will light. And in ninety seconds the surge will come in here, not there, because the Flood goes to the lit beacon.

You could instead take the tool on your back, a coil that stores a charge, wade into the channel wearing insulation, and discharge it. The water carries the current to the hatch and it opens for a few seconds: long enough to get through. The yard stays dark. The surge still goes to the causeway. But you have spent the charge you spent the last surge harvesting.

Or you could do what the experienced player does: throw the switch, let the hatch open, stand in the channel's edge in insulation, and wait. When the surge wades into the water to reach the beacon, you discharge the coil into the water they are standing in. They stop, stunned, and shed charge you can pick up. The hatch is open. The battery is full. You invited the Flood into the water where your coil was waiting.

The rule is the same in all three. What differs is what you knew.

2. The district

One fixed district, revisited every expedition. Its layout never changes; what varies is which modules and salvage are where, and how big and when the surges are. The map below is the World and Mystery Designer's, adopted as drawn; it is a design aid, not a floor plan. North is the interior, the docks are south; = is raised and dry, ~ is shallow water, - is the culvert.

                        INTERIOR  (tier two: the valve gallery;  tier three: the relay room)
                                  |
                   SLUICE  (the Flood's own way in: no beacon; "off" sends the surge here)
                  /                                      \
   GATE  [causeway beacon] ===== causeway intake      [yard beacon] PUMP HALL (hatch, tally board, ladder up to the yard ledge)
   at the causeway's far end                           yard intake = the channel mouth ~~~ in front of the hall door
        ||  raised causeway, signed "refuge"                ~~ yard channel ~~   deposits on both banks
        ||  causeway ledge, mid-span (shelter)              ~~ yard ledge, dry, beside the channel (shelter)
        ||------------------- culvert ------------------- culvert exit, yard bank
   culvert exit, dock end
        ||
   PANEL at the causeway head
        ||
   CAUSEWAY DOCK (held dry by default)                  YARD DOCK (flooded by default; wet ground, conducts)

• Docks. Two, on the rim. The causeway dock is dry by default and is where you start and leave. The yard dock is flooded by default: wet ground, unusable, until the colony's pump holds it dry instead of the causeway dock (the colony's one standing choice, section 10). A dry dock is a shelter: enemies neither enter nor spawn there.
• Causeway. A raised dry road from the causeway dock into the district, signed as the evacuation route. Its beacon is at its far end, lit by default, and beside the beacon stands the gate into the interior, the causeway branch's one powered device: open while the causeway is lit, shut otherwise. A dry ledge halfway along is a shelter. The panel stands at the near end, the causeway head, in the open, about eight seconds from the dock.
• Culvert. A drain tunnel under the causeway joining the two dock ends: a gravity drain, dry on its own, never pumped, never paid for. Walkable, with cart wear on the floor and a refuge sign turned to face the yard. One exit at the dock end, one on the yard bank.
• Yard and pump hall. A salvage courtyard on both banks of a shallow channel. The channel enters the yard in front of the pump hall's door, and the yard's beacon stands there, dark by default, so a surge that enters by the yard arrives standing in water. The pump hall's hatch is the yard branch's one powered device, on the same circuit as its beacon: powered, open; unpowered, shut. Inside the hall are the crew's tally board, a dead pump, and an unpowered ladder up to the yard ledge, a dry shelter beside the channel. Three salvage deposits are on the banks.
• Sluice. At the district's low end, where the two branches meet, a water gate with no beacon: the Flood's own way in when neither branch is lit. It opens onto the interior route.
• Interior. Beyond the gate: the valve gallery (tier two) and the relay room at the sluice's head (tier three), section 11. Not part of the first expeditions.
• Shelters. The two docks when dry, the causeway ledge and the yard ledge. Repacking happens only in shelters.

3. Core play

Controls (proposal). Top-down 2D. Keyboard and mouse or gamepad. Move with the stick or keys. The cutter fires by itself. One button triggers the coil. One button interacts (panel, valve, ladder, deposit, inspectable prop). One button opens the notebook. One button plants or retrieves a beacon. The rack is rearranged by dragging, only in a shelter.

Combat. The cutter is a handheld tool that fires by itself at the nearest organism in reach while you move; you aim by where you stand. About three hits kill one organism, at roughly two hits a second. A surge is forty to a hundred and forty organisms arriving over half a minute, so you cannot kill your way through one; you can thin its edge, hold a doorway where they come one at a time, or stun a mass standing in water with the coil.

Health. A short bar, five hits. Touching an organism costs one, with a moment of immunity after. Standing in energised water without insulation costs one per second. Health does not regenerate in the district. Leaving by a dock restores it. A found kit module restores it once and costs a rack slot.

Surges and the forecast. The district's relay still runs on its old timer. At each scheduled tick, a dispatch, it sends a pulse down the line the panel has selected, the beacon on that line flashes, and a surge comes in there. Three dispatches per expedition, at roughly three, eight and twelve minutes, each surge larger. The forecast is the relay's own schedule, read from a board at the dock and shown as a countdown and a map marker at the intake. It exists because the district always had it; it is the Flood's timetable only because the Flood follows the pulse.

Room to think: three rules.

• Notebook. Opening it pauses everything. It shows only what you have already seen: your map, your notes, the rules you have observed. It never adds evidence.
• Shelter. A dry dock or either ledge is a hard stop: enemies neither enter nor spawn. You can repack and watch the district from it. The surge clock keeps running, so retreating to think costs time and position, never health.
• Live evidence. New clues, switches and experiments happen in the running world.

Failure and ending. After the third dispatch the evacuation window opens: reach a dry dock within three minutes. Missing it, or losing all health, means rescue: you get out, without your cargo. Death costs cargo and whatever modules you found this expedition; it never costs notes, banked salvage or colony state, and the starting kit is reissued, so there is no loss spiral. Retry is immediate.

4. The one rule, stated once

Everything below is a consequence of four clauses. They apply identically to the district, to the rack on your back, and to the colony's dock.

1. Conduction. Current flows between touching conductors, and through water to everything the water connects. Insulation stops it.
2. Power. A device works only while it is energised: a hatch, lamp or beacon on a live line or in energised water; a rack module linked to a charged battery. A lit beacon is steady while powered.
3. Attraction. The district has two kinds of line: a power line and a signal line, both switched by the panel to the causeway, to the yard, or to neither. At a dispatch the relay's pulse travels the signal line only, the beacon on it flashes, and the surge enters there. The panel alone decides the intake. After entry, a surge moves toward the nearest lit beacon it can reach, re-evaluated continuously, and gathers around it when it arrives; with no lit beacon reachable it spreads along the branch it entered. Current you inject yourself (the coil, a planted beacon's battery) travels power, never signal: it can light a beacon steady and open a hatch, so it can draw a surge that is already inside, but it can never choose where the next surge enters.
4. Charge. Organisms carry charge. A killed one drops a small mote; a mass stunned in water sheds large motes. Each organism sheds once per expedition and is visibly dimmer afterward. Motes fade in seconds; walking over one fills a battery in your rack; with no battery, the charge is lost. Charge never leaves the district.

What this gives the player, in plain terms:

• A valve that joins two channels extends where current reaches. A field pump, fuelled by a bundle of salvage, drains a channel and cuts it. The coil injects current. The panel routes it.
• The lit branch is the branch the Flood comes to. Powering the yard to open its hatch means the next surge enters the yard. That is the price of every door.
• Switching the panel mid-surge moves the Flood, and that is its price. Throwing the panel from causeway to yard darkens the causeway beacon and lights the yard's. Every crowd already inside walks to the new light: from the causeway's far end, down across the junction below the sluice, and along the channel to the yard beacon, so the interior route is occupied while it crosses. The gate at the causeway's far end shuts behind it, so anyone inside the interior comes back by the yard. Yard to causeway is the mirror, with the hatch shutting. Off darkens both: every crowd spreads along its own branch, toward the docks as much as the interior, and both devices shut. The forecast shows each entered surge's new target the moment you switch, so the price is readable before the crowd moves. And the panel stands in the open at the causeway head. So a panic switch does buy something this surge, and it is meant to; what it costs is the route the crowd crosses, the door that shuts, and where the next surge lands.
• Surge behaviour after arrival. A surge gathers around its target beacon and holds there while that beacon stays lit and no lit beacon is nearer. Each surge is larger, so the held crowd's radius grows; by the third the causeway's far end or the channel mouth is full. Two things pull organisms out of a crowd: proximity, any organism within a short radius of the surveyor pursues regardless of beacons, which is what the cutter fires at; and thinning, over a quiet interval the crowd drifts outward along its branch and into the water as stragglers, so "quiet" means spread thin, not gone, and the next surge re-concentrates it. A surge whose beacon goes dark spreads along its branch at once, both ways. What makes a held crowd a decision: the gate, the hatch, the richest deposits and the motes all sit at the far ends where the crowd is, so harvesting or opening anything means working at the crowd's edge inside its proximity radius, or waiting for thinning and losing surge time. At the end of the expedition everything resets.
• Dock consequence. Extraction is threatened by two things only: a planted beacon lit near a dock, or a dark branch with a crowd in it spreading toward the dock. So the held dock's branch must stay lit whenever a surge is in it, which is also what keeps that branch hot. Holding the causeway dock means the causeway is your safe default and the yard is where you send trouble, with the culvert as the road home under the crowd. Holding the yard dock means the yard must stay lit through any surge you send there, so the hall's crowd stands between you and nothing, but off and causeway are both dangerous the moment a surge is in the yard, and the yard has no culvert of its own. The colony's choice decides which branch you can never afford to darken. A surge never blocks a dock, because a dry dock is a hard stop; it makes the route to it cost something.

An alternative the owner should know about. The world designer and I had converged on a stricter version of clause 3, in which a beacon pulls only within a visible glow and the two fixed beacons are out of each other's sight, so the panel could never move an arrived surge and only a carried beacon could. It keeps the panel a pure planning tool and removes the panic switch. PM chose the simpler continuous rule for this draft so that one model is written out fully and priced. Both are on the table; the difference is whether the panel is a plan or a lever. Neither has been played.

5. Gear: the rack and three loadouts

The rack is the frame on the surveyor's back: six slots in two rows of three. It is the whole inventory apart from the cutter, which needs no slot. Each slot holds one module or one bundle of salvage.

Rack rules, from clause 1:

• Modules have insulated housings and do not conduct, powered or not. Salvage is dredged wet and conducts, and wet bundles pass current onward to bundles they touch.
• When packing, you draw one link from each battery to the one module it powers. An unlinked module is dark and inert.
• A battery leaks into every bundle connected to it by touching bundles, whatever the links say: one unit a minute per connected bundle, shown as a drip per bundle. Insulation is the only slot that breaks a chain.
• A battery holds ten units. A discharge of the coil spends the whole battery. A kill mote is one unit; a stun sheds one large mote of five units per ten organisms stunned.

You leave the dock with the cutter, one empty battery in an otherwise empty rack, and whatever starting module the workshop lets you choose. All numbers are proposals.

Modules in the minimum scope: battery (1 slot), coil (2 slots, horizontal or vertical), insulation (1), beacon (1), kit (1), siphon (1: consumes one touching bundle for three units of charge, once, for the player who needs power and has only salvage), and, if the owner wants the genre's payoff moment, the arc (section 6). Six or seven types; the concept's ceiling was ten.

What the rack is and is not. It is a small item game on purpose: six slots, a handful of modules, one conduction rule, and three named loadouts. It is not the game's pillar of expression by itself, and an owner expecting a grid-inventory game with hundreds of items should not expect it here; that would be a different product with a different content budget. Expression in this design is the combination of loadout, panel setting, route and held dock, and the rack's job is to make the loadout half of that visible and slightly costly. If the owner wants the rack to carry more, the honest cost is module count, roughly twenty to thirty with real interactions, and that is a scope decision, not a tuning one.

Three loadouts. Rows are top and bottom; letters are C coil, B battery, I insulation, P beacon, S salvage bundle, K kit, and a dash is empty. Links are stated.

The electrician.

C C B
S S I      link: B → C

The battery touches the coil (linked) and the insulation; the insulation stands between the battery and the bundles, so nothing leaks. Two bundles. Play: set the panel to yard on purpose, stand in the channel's edge in insulation, wait for the surge to wade in, discharge: stun, large motes, and the hatch already open by the panel. Cost: four of six slots on gear, one full battery per discharge, and you must be standing in the water you electrify. Counterplay by the district: the surge only sheds once, so stunning the same crowd again yields nothing; a discharge during a quiet interval opens a door but harvests nothing; if the panel is thrown while you are inside the hall, the hatch shuts behind you. Best when a surge will stand in water and you have the charge to greet it.

The hauler.

S S S
S S S      cutter only; no battery, so motes are lost

Six bundles. Play: leave the panel on causeway, take the culvert to the quiet, dark yard, gather, come back under the surge. Cost: never opens a powered door, never harvests, has no answer to a surge except distance. Counterplay: anything that lights the yard, including another player's habits from an earlier expedition (the panel resets, but a coil-lit beacon does not need the panel). Best on the expedition after a discovery, when you know exactly where the salvage is and how to avoid the road.

The shepherd.

S P B
S S I      link: B → P

The beacon and its battery are packed together; the insulation keeps the battery off the bundles. Three bundles. Play: carry the lit beacon into a surge's reach and plant it; the surge walks to it and stays while it is lit. Planting sets down the beacon and its battery as one piece and frees two slots; retrieving is walking over it. Darken it (retrieve it, or let the battery run down) and the pull stops. Cost: the beacon draws the surge toward wherever it is, including you while you carry it; its battery runs down while planted; and it can pull only what is already inside, never choose an intake. Counterplay: a lit fixed beacon nearer the surge outcompetes it; a surge pulled off one route occupies another. Best for clearing the interior route for a run at a distant deposit, or for pulling a surge off the causeway so the hauler's road is clear.

A readable failed arrangement.

B S S
C C S      link: B → C

The battery is linked to the coil below it, correctly. But it also touches the bundle to its right, which touches the next, which touches the one below: three connected bundles, three drips, three units a minute. The battery is empty in a little over three minutes, before the second surge, and the coil is dead when it is needed. The fix is visible in the rack: move the insulation between, or leave a slot empty, and carry less.

6. Growing inside an expedition

Kills give no experience. The reason is a design bet, not a law: in a game about routing a crowd, rewarding kills per se pulls the player toward the biggest crowd and away from the district, and this design wants the district to be the reward. What kills give instead is charge, which is fuel for experiments, and fuel is only worth harvesting if you have somewhere to spend it. Whether that keeps moment-to-moment fighting satisfying is an open question for play, not something this document can settle.

Growth comes from the world. Per expedition, two to four modules from fixed placements whose contents vary; two to six bundles from deposits; and charge from surges met on your terms. The rack caps at six slots, so power grows by composition, not by number: you leave with a cutter and an empty battery; by the second surge you usually have one powered setup; the third surge tests it. Later expeditions grow faster because the workshop lets you start with a chosen module and because you know where the placements are.

Charge is finite by rule. Each organism sheds once. A surge of forty stunned in water yields four large motes, twenty units, two full batteries, if you are standing where they fall before they fade. Stragglers yield one unit each. Discharging spends a whole battery. So the electrician's loop, harvest a surge to fund the next discharge, pays only against a fresh surge standing in water, and never against the same crowd twice.

The genre's payoff moment, and an optional module to supply it. Crowd games of this kind have one defining moment: the point where your power outpaces the spawn rate and you mow the crowd down. This design's arc does not reach that point by default, and an outside critic is right that shipping under the genre's tag without it risks disappointing the audience the tag brings. One on-rule addition would supply it without kill experience: the arc, a one-slot module that, while linked to a charged battery, makes the cutter's hits conduct from organism to organism through a dense crowd, draining the battery over about twenty seconds. In a thin crowd it does little; in a packed surge it is the mowing moment, funded by charge you harvested from the surge before, and bounded by the finite-charge rule so it cannot be sustained. It is the same conduction clause, applied to bodies. Whether to include it is the owner's call (section 17); with it, the design has the genre's spike as a spend rather than a climb.

7. Exploration

The district is small, fixed and dense, and it is meant to be re-read. Landmarks are the two beacons, the panel, the culvert's turned sign, the pump hall, the sluice, the gate and the two ledges. Routes are few and named: the causeway, the culvert, the channel edge, the interior route. Revisiting is the whole structure: the same place means something different once you know what its light means.

What you can discover, and what each discovery changes:

Knowledge is the persistent progression. No discovery is gated behind a module or a stat: the panel works on the first expedition; what changes is knowing what it does.

8. Experimentation

The player experiments in two places under one rule: in the district (valves, the panel, the coil, a planted beacon, a field pump) and in the rack (what touches what, what is linked). Every experiment has a visible cause and a visible cost.

• Limits. The panel powers one branch or none. A discharge needs a full battery and spends it. A field pump costs a bundle and lasts one expedition. A planted beacon runs its battery down. A stun yields once per crowd.
• Combinations that matter. Panel to yard plus a coil in the channel: stun and harvest an invited surge. In the interior's valve gallery (tier two), a valve joining the two branches' water plus a coil discharged in the yard channel: light the causeway beacon and open the gate from the yard side, without touching the panel and without changing the next intake. A planted beacon on the causeway's dock end plus the panel on yard: pull an entered causeway crowd off the road while the next surge goes to the yard, clearing both routes home for one interval, at the cost of a crowd gathering near the dock you will leave by.

A plausible experiment that fails, readably. The player has learned that current opens the pump-hall hatch and that the yard is dark. Surge one is gathered at the causeway beacon. The player wades into the yard channel and discharges the coil to open the hatch without touching the panel, reasoning that the yard stays dark to the relay and the surge will stay on the causeway. The hatch opens. So does the yard beacon: it lights steady, because it is on the same wet circuit. Surge one, which follows the nearest lit beacon it can reach, turns off the causeway and comes to the yard, through the junction, while the player is inside the hall. The lesson is legible in the light convention: steady means powered, powered means lure, and the coil powers everything the water touches. The recovery is in section 13.

9. The mystery: the false refuge

Designed with the World and Mystery Designer; this section takes their corrected revision when it lands. The solution is a designer spoiler; the owner should read it, players should find it.

The question the player is asked by the place. The causeway is signed as the evacuation route. It is where the Flood is. The culvert beneath it, unmarked, has cart wear and a refuge sign turned to face the yard. Why is the marked refuge overrun while the passage beneath it still looks used?

Knowledge, not equipment. The panel is usable on expedition one; nothing about the deduction needs a module, a resource or a flag. Equipment changes how well the choice can be exploited, never whether it can be made. If a clue is missed: the causeway beacon is steady on every arrival and flashes every dispatch; the culvert is visible from the yard side too; the marker jump is a second, independent way in; optional hints escalate from "the two beacons differ" to "switch, then watch the forecast marker". After death: notes, map and observed facts persist; no deduction is granted unearned. After the answer: the question closes; the decision does not. The same dispatches, the same panel, a different loadout, cargo target and held dock make the routing choice fresh each expedition. Diverting never creates extra enemies or rewards.

10. Progression and persistence

The colony is the dock and its pump, and the people on it. It is deliberately small, and it makes exactly three kinds of decision:

• Which dock is held dry. One exclusive standing choice. Changing it costs a full return's salvage. It inverts which panel setting is comfortable (section 4) and where the coil works, because a flooded dock is wet ground.
• The workshop. One additive repair, a full return: lets you choose one starting module each expedition instead of leaving with only a battery.
• The forecast relay. One additive repair, a full return: the first intake is known before you leave the dock, so the first three minutes can be planned.

No upkeep. Salvage repairs and improves the colony; nothing decays between expeditions, nothing is charged per expedition, and repeated failed expeditions lose nothing already banked. The colony's stake is long-run: every repair, every change of held dock, and the ending itself are paid in salvage, so a surveyor who stops hauling can never change anything. This is a drafting default: the alternative, a per-expedition pump cost, would punish an investigative expedition that returns light, which is the meta-level version of pressure that leaves no room for curiosity. If the owner wants the colony to feel more precarious, the place to add it is the ending's cost, not a tax.

Is that enough colony? Honestly: it is a small colony by the standard of colony-management games. Its decisions change the value of what you know rather than adding systems, which is the intended relationship. If the owner wants a larger settlement, with people, needs and building, that is a scope decision that adds a second game to this one and should be made knowingly.

11. The whole game

One district and an ending. The mystery has three tiers, each a recombination of the same rule in the same district, not a new machine family.

• Tier one, the false refuge (expeditions one to about three). Why the causeway is overrun. Answered in the pump hall. Changes routing for good.
• Tier two, the interior (about four to seven). What the last crew went in for. The inked route leads through the gate at the causeway's far end, which is open only while the causeway is lit, so the door to the interior and the Flood's road are the same branch. Beyond it, the valve gallery: the crew's second repurposing. Valves that join the two branches' water, so that a beacon can be lit from the other branch's current without the panel. Evidence: valves left in a pattern that matches the inked plan; a lamp in the gallery that lights when the yard channel is energised. Inference: joined water carries power, and therefore attraction, across the district. Experiment: join the channels and discharge in the yard, and watch which lamps and which crowds respond. Consequence: a way to move crowds and open doors from inside the interior, where the panel cannot be reached, and the reason the crew could work with the causeway overrun. The answer is a second tally board and the crew's key to the relay room.
• Tier three, the relay (about eight to eleven). The relay's timer, in a room at the sluice's head, is what calls the Flood. The final choice, each an expedition-ending act that leaves a different district: shut it, so there are no more dispatches and the Flood enters only by the sluice, unannounced, honest and harder; fix it, welding the panel to one branch for good, one dock safe forever and one branch lost; or hold it, leaving it running and keeping the steering, the status quo chosen. Reaching the room and choosing ends the game. Free expeditions continue after any ending.

Early, middle, late. Early, you learn to read light and to use the culvert. Middle, you carry power to places the panel cannot reach and learn to hold a surge where you want it. Late, the district is a machine you play, and the ending asks what you want it to do.

What is different on expedition nine that was not on expedition six. An outside critic put the hardest question well: once the map is memorised and the notes persist, what renews? The honest answer has three parts. First, the decision renews even when the knowledge does not: every dispatch is a fresh choice of where the Flood lands, and its right answer depends on this expedition's loadout, cargo target, held dock and which crowd is already where; the same three dispatches never pose the same problem twice. Second, the district is not fully known by expedition five, because tiers two and three open the gate, the gallery and the relay room, each of which changes what the rule can do rather than adding rooms to memorise. Third, the surges vary in size and timing within the schedule, and placements vary, so a route is a plan, not a script. What does not renew is discovery itself: once the three tiers are solved, the game is finished, and the design says so rather than pretending to be endless. If the owner wants more life after the ending, the extension with the best return is a second district under the same rule, and it is a scope decision.

How long the game is, in hours. Counting what is designed, the minimum is about ten to twelve expeditions, three to four per tier, with deaths adding to that; at about fifteen minutes each, that is roughly three to four hours for the whole designed experience, ending included, before free play. This is an estimate from content, not a validated length; the earlier figure of twelve to twenty expeditions was a guess. The owner should know one commercial fact that follows: a storefront refund window of two hours would cover about the first eight expeditions, which is most of the designed game. That is a pricing and scope constraint, not a design flaw, and section 17 puts it in front of the owner as a decision about length and extensions.

The title. Hold the Flood is the owner's title. In this design the holding is done by deciding where the Flood goes: the colony holds the Flood off its refuge not by fighting it but by routing it, and the ending is about holding it for good. The Flood is the enemy mass, never the water; the water is what carries the current.

12. Expedition one (illustration, not a playtest)

A first-time player. Panel untouched, on causeway. Causeway dock held dry. Starting kit: cutter, one empty battery. Times are approximate and proposed.

0:00. The dock. The forecast board reads: first surge in three minutes, intake causeway. Ahead, the causeway; its far-end beacon is lit steady. To the right, a dark tunnel mouth: the culvert. The player takes the culvert because the causeway looks like where the trouble is.

0:40. The culvert. Cart wear on the floor, heading away from the causeway. A refuge sign on the wall, turned to face the far end. The player inspects it: three lines of text. The notebook records both.

1:30. The yard. Salvage deposits; the player gathers two bundles into the rack. A module placement in a wrecked cart: a coil. It goes in the rack, unlinked. The shallow channel runs past a shut hatch into a dark pump hall; a cable runs from the hatch along the channel to a dark lamp on a post at the hall door. The player inspects the lamp: dark, and the notebook records it.

3:00. The dispatch. From the yard the player sees the causeway beacon flash across the district and, a moment later, the surge pour in at its far end and gather there. Forty organisms. The forecast now reads: second surge in five minutes, intake causeway. The notebook records: the surge came in where the lamp flashed.

3:30 to 7:30. Quiet. The player climbs to the yard ledge, a shelter beside the channel, and watches the causeway crowd thin slowly down the road toward the dock end. Two stragglers wander into the yard; the cutter kills them; two motes; the player walks over them and the battery shows two units. On the ledge the player links the battery to the coil, then finds a third deposit on the far bank. Rack now: coil, battery, three bundles, one slot empty, and one drip, because a bundle touches the battery. The player does not yet know what a drip means.

8:00. The second dispatch. Causeway again, eighty organisms, joining the first crowd. The press on the causeway now reaches halfway to the dock. The forecast reads: third surge in four minutes, intake causeway. The player decides to leave.

9:00. The culvert, back toward the dock end. The player emerges at the causeway head, twenty metres from the dock, with the press's edge thirty metres up the road. Four organisms break off and pursue. The cutter takes two; the player takes one hit; the dock is a hard stop and the pursuers stop at its edge.

9:40. Extraction, three bundles and a coil, one point of health down, a battery with two units minus what leaked. The player banks three bundles. The notebook holds: the culvert is safe and marked; the surge comes in where the lamp flashes; the yard lamp is dark and the hatch is shut; there is a switch at the causeway head with cables to both lamps.

Nothing was solved. Everything needed to solve it was seen.

13. A later expedition, changed by knowing (illustration)

Expedition six. The player has solved the false refuge, banked enough for the workshop, and chooses the coil as the starting module. Loadout: the electrician, from section 5. Causeway dock still held dry.

0:00. The forecast reads: first surge in three minutes, intake causeway. The player leaves the panel alone and takes the culvert to the yard, gathers two bundles, and waits at the channel's edge.

3:00. Surge one, causeway. The player ignores it. Two stragglers, two motes; the battery reads two.

4:00. The player runs the culvert back, dashes the eight seconds to the panel, and throws it to yard. The yard lights. Across the district, surge one leaves the causeway beacon and starts toward the junction. The forecast reads: second surge in four minutes, intake yard. The player returns through the culvert at a run.

6:00. The yard. The hatch is open. The player enters the pump hall and reads the tally board again, this time looking for the inked route, and copies it. Outside, surge one arrives at the yard beacon, in the channel at the hall's door, and gathers. The player is inside with the Flood at the door. This is the moment the design is built around.

Options, all readable: the hatch is powered and open, so the door is a chokepoint where organisms inside the proximity radius come in one at a time, and the cutter can hold it for a while at a cost in health; or the player steps to the channel's edge inside the doorway, in insulation, and discharges the coil into the water the crowd is standing in. The battery has two units; a discharge needs ten. So the player holds the door with the cutter, kills eleven, picks up eleven motes between the bodies, and now has enough.

7:50. Discharge. The crowd in the channel stops, stunned for eight seconds, and sheds four large motes. The player walks the channel's edge collecting them, battery full again, and is clear of the crowd before it moves.

8:00. The second dispatch, yard, eighty organisms, into the channel where the stunned crowd is recovering. The player is already on the culvert side.

8:30 to 11:30. The player takes the causeway, now empty, to its far end, following the inked route. The gate into the interior is shut: it is on the causeway circuit, and the causeway is dark because the player lit the yard. To go in, the causeway must be lit, which means the next surge comes to the causeway, the road home. The player writes it down: the door to the interior and the way out are the same branch. Not this time; the full battery is the way home.

12:00. Third dispatch, yard. The player is on the causeway, walking home along the road that was, five expeditions ago, the Flood's. Extraction with three bundles, a full battery's worth of charge unspent and lost at the dock, and the interior route copied.

What the hatch does when power ends. If the yard loses power while the player is inside the hall, because the panel was thrown elsewhere or a coil-opened hatch timed out, the hatch blinks for three seconds and closes, and anyone inside is shut in. Every hall has an unpowered exit: here, the ladder up to the yard ledge, a dry shelter beside the channel. Climb, wait, and come down to the bank or take the culvert. The trap is recoverable without solving anything, and the recovery costs surge time, which is the currency this design charges in. Switching the panel from inside is impossible, because the panel is at the causeway head.

14. Presentation and assets

Direction. Top-down 2D, one small district, readable at a glance. One light convention carries the whole rule: steady means powered, flashing means a dispatch, dark means unpowered. Wet and dry are a tint. Energised water shows arcs. The rack is a six-cell panel with drawn links and drip icons. No AI-generated art of any kind; existing free assets first; purchases and custom assets only with the owner's approval.

Readable states and their cheapest medium. Sources are listed only where their terms were actually read today; nothing else is claimed.

Sources checked today, read-only. OpenGameArt's published FAQ states that hosted assets are offered under one of CC0, CC-BY 3.0/4.0, CC-BY-SA 3.0/4.0, OGA-BY 3.0/4.0 or GPL 2.0/3.0, that each asset carries its own uploader-chosen licence, and that commercial use is allowed under those terms; no specific pack has been selected. Kenney's asset listing page does not state a licence on the listing itself, but the individual page for its "Top-down Shooter" pack states "Creative Commons CC0" and describes 580 files of 2D top-down sprites including tiles, furniture and zombie-style figures; that makes it a plausible candidate for tiles, props and a reworkable creature sprite, subject to a suitability check nobody has done yet. No asset has been downloaded, purchased or created.

Coverage gaps, honestly. The enemy sprite is the likely custom-art request. Everything else in the table can be carried by generic top-down tiles, a UI kit, engine particles and text, at the cost of some atmosphere. Sound is not designed here.

15. Scope

Minimum complete experience. One district (two docks, causeway with gate and ledge, culvert, yard with pump hall and ledge, sluice, the valve gallery, the relay room), three mystery tiers, six or seven module types, one enemy type with size and tint variants, three surges per expedition, three colony decisions, an ending. About ten to twelve expeditions, three to four hours.

Optional extensions, in order of value. A second district using the same rule with different geography. A second enemy variant that conducts differently. More module types. A larger colony.

Explicit cuts. No fluid simulation: channels are wet or dry. No destructible terrain. No free chemistry. No procedural layout: the district is fixed and the mystery depends on that. No base-building grid, citizens, hunger or production. No multiplayer. No kill experience.

Complexity drivers. Crowd behaviour with holding, thinning and proximity pursuit (the one real engineering risk). Readable energised water. The rack UI. The forecast overlay.

Cheap alternatives if needed. Thinning as a fixed radius that grows on a timer rather than simulated crowding. A single fixed proximity radius. Text inspection for every clue prop. Flat tints for water states.

16. Honesty: what is resolved, what is open, what is unknown

Resolved in this draft. One routing model, written out and priced (section 4), on the world designer's map. The yard intake is in the water. Modules do not conduct; wet salvage does, and passes it on. Charge is finite by rule. No colony upkeep. The culvert is a gravity drain and costs the player nothing. The hatch has a stated closing rule and an unpowered exit.

Presented for decision, not resolved. The routing alternative (sight-limited beacons). The ending's shape and the game's length. The colony's size. The rack's size. The genre's payoff module. The enemy's identity, its name and the drowned-city setting. The presentation assumption.

An outside critique, answered where it is this document's to answer. A critic outside the recorded team has posted a market and originality audit; PM has not yet ruled on its standing, and nothing in it is treated here as an assignment. Four of its points are design questions and are answered above on this page's own terms: what the rule does that its inspirations do not (section 1), the rack as a stated small scope (section 5), the genre's payoff moment (section 6), and the renewable after the mystery is solved with the game's honest length (section 11). Two are the owner's: the enemy's name, since the critic reports that "the Flood" is the name of a well-known existing game's enemy faction and the owner's requirement fixes the meaning of the term rather than the string, which I have not independently verified but is cheap to check and cheap to change; and whether audience, comparables and length should join the document criteria. One is PM's and the critic's to settle between them.

Unknown until played. Whether the deadline produces planning or anxiety. Whether fifteen minutes and three surges leave enough observation time. Whether the panic switch dominates. Whether a crowd's press and pursuit read on a busy screen. Whether "no kill experience" leaves fighting satisfying. Whether the leak rate makes the rack a decision or a nuisance. Whether ten to twelve expeditions is enough content. Nothing here is a claim of tested enjoyment.

17. Decisions the owner needs to make

1. Confirm or redirect the premise. Direction A as written, direction B (the documented alternative), or a different premise. A is PM's provisional choice, not yet yours.
2. Enemy and setting. Bioelectric organisms in a drowned pumping district are proposals. If you want zombies, aliens or another Flood, the rule survives; the fiction changes.
3. The routing model. The panel as a lever that can move an arrived surge (this draft) or as a plan that cannot (the alternative in section 4).
4. The ending and the length. One district with an ending at the relay, about three to four hours, as proposed; or an open-ended game; or the proposed game plus a second district as the extension that adds the most. Know that a two-hour refund window covers most of the minimum as designed.
5. The colony's size. Three decisions and no upkeep, as proposed, or a larger settlement, which is a second game.
6. No kill experience, and the payoff moment. Charge as the only combat yield, as proposed; and whether to add the arc module so the genre's mowing moment exists as a spend. Without it, the honest label is a routing game with automatic weapons rather than the genre as its audience knows it.
7. The rack's size. Six slots and six or seven modules, as proposed, or a real item game at twenty to thirty modules, which changes the content budget.
8. The enemy's name. "The Flood" is your term for the enemy mass; an outside critic reports it is also the name of a well-known existing game's enemy faction and that the phrase is hard to find on a storefront. Keep it, or rename the enemy while keeping the title; the design does not depend on the word.
9. Presentation. Top-down 2D, as assumed.
10. Assets. Expect one custom-art request, the enemy. Nothing is requested yet.

Development remains unauthorized until you have read this and said so explicitly.

Appendix A: words used above

• Survivorlike: a game where you steer one character through ever-larger crowds of enemies while your weapons fire by themselves; your hands move, dodge and position, and your choices are where to go and what to carry.
• Expedition: one trip from a dock into the district and back. The Brief's "run" means the same thing.
• The Flood: the massed enemies (owner requirement). Proposed here as bioelectric organisms.
• Surge: one wave of the Flood entering the district.
• Dispatch: the scheduled instant the relay releases a surge and pulses the selected beacon.
• Relay: the district's old automatic timer and transmitter.
• Forecast: the relay's schedule, shown as a countdown and an intake marker.
• Intake: where a surge enters: the causeway's far end, the yard channel at the pump hall, or the sluice.
• Beacon: a lamp on the district's circuit; steady when powered, flashing at a dispatch, dark when unpowered. A lit beacon draws the Flood inside the district.
• Panel: the three-position switch at the causeway head that decides which branch's power and signal lines are live.
• Power line / signal line: the two lines the panel switches; power lights and opens things, signal carries the dispatch pulse.
• Thinning: the slow drift of a gathered crowd outward along its branch during a quiet interval.
• Proximity radius: the distance within which organisms leave a crowd to chase you.
• Gate / hatch: each branch's one powered door: the gate into the interior at the causeway's far end, the hatch into the pump hall. Open while their branch is lit.
• Ledge: a raised dry shelter, one mid-causeway and one on the yard bank beside the channel.
• Shelter: a dry dock or either ledge; enemies neither enter nor spawn there.
• Arc: an optional module that makes the cutter's hits conduct from organism to organism while it drains a battery.
• Rack: the six-slot frame on the surveyor's back; the whole inventory apart from the cutter.
• Module / bundle / cargo / salvage: a module is a piece of gear; salvage is the material the colony needs; a bundle is one slot of it; cargo is the bundles in your rack.
• Link: the drawn connection from a battery to the one module it powers.
• Leak / drip: charge lost from a battery into connected wet bundles, shown as a drip per bundle.
• Coil, insulation, beacon (module), kit, siphon: the modules, section 5.
• Cutter: the handheld tool that fires by itself. Needs no slot.
• Charge / mote: the Flood's shed energy; a mote is a dropped fleck of it.
• Loadout: the modules you carry and how they are arranged. Older pages say "build"; this document avoids that word because the Hub uses it for compiled software. Loadout expression is the way a loadout shows a strategy.
• Knowledge gate / stat gate: a knowledge gate is passed by understanding something; a stat gate is passed by having a number high enough. This design uses only the first.
• Telegraphed: announced before it happens. Counterplay: what the district or the Flood can do against a loadout, and what the player can do back. XP: experience points, the per-kill growth this design does not use.
• Field pump: a pump fuelled by one bundle that drains one channel for one expedition.

Appendix B: bookkeeping

Status. DES102 draft r2, In review, on Hold the Flood/Design Document; r1 (d828a4) is page history. Author: the Lead Game and Systems Designer, the session PM identified as canonical in Brief D014. Written under Brief D013 (direction A, provisional, reversible) and Tasks PMR001. The design-only gate (Brief D007) is unchanged: nothing has been built, prototyped, simulated, tested or drawn.

Sources read. Hub 89e2dc; Brief 3cf14c; Tasks ee938e (PMR001); Team 3ddc81; Design r6 211106 (the accepted concept packet is r4, 42f653); World and Mystery r8 ba6f8b (WLD102, the exact revision the world designer handed over; r9 41681d changes only their PM report); Design Review r7 bb6871; Clarity Questions 45c6a9; Glossary 86c1c4; PM Reviews (PMR001 checkpoint); External Critique r1 (EXT101, standing not yet ruled on by PM).

What r2 changes. Integrates WLD102 r8 as delivered: the world designer's map (interior gate on the causeway circuit, two ledges, culvert exits, the ladder from the hall to the yard ledge as the unpowered exit), the gravity-drain culvert, the crowd vocabulary (holding, proximity, thinning), the re-derived dock consequence, the mid-surge price by route and door, the mystery's revised rows, and the shut / fix / hold ending with the valve gallery as tier two. Answers the outside critique where it is design: the differentiator (section 1), the rack as a small scope (section 5), the optional arc module for the genre's payoff (section 6), the renewable and the length in hours with the refund-window fact (section 11), and three new owner decisions (section 17). The routing baseline is unchanged from r1 and from D013; the world designer's r9 asks PM to confirm or reverse it, and this document is written so that either answer changes section 4 and the scenes, not the rest.

PMR001 corrections, where each is answered.

1. One routing model: section 4, clause 3 and the plain-terms list; PM's baseline adopted; sight-limited alternative presented for decision; the coil cannot select intake because signal and power are separate lines; every scene (sections 1, 8, 12, 13) rewritten under this model; W2 reduced to intake commitment.
2. Extraction and dock consequence: section 2 diagram; section 4 surge behaviour (press, pursuit, dispersal by reset), dock consequence, no blocked dock; section 12 untouched-panel retreat; section 13 pump-hall moment with hatch closing rule and the ladder exit; the yard intake in water carried into the topology.
3. Rack: section 5, nonconductive modules, onward conduction through bundles, three drawn loadouts with links, starting-kit wording, planting and retrieval, one failed arrangement, numbers labelled proposals.
4. Charge: section 4 clause 4 and section 6, once-per-organism yield, discharge cost, the kill-experience reasoning restated as a bet with its uncertainty; combat rules carried into sections 12 and 13.
5. Ending without a tax: sections 10 and 11, no upkeep, three tiers in the same district, one path, expedition count as an estimate, title related to holding enemies off the refuge.
6. Readability: plain body, Appendix A with the five requested terms, the readable-state table in section 14 with sources checked today, the culvert's pump account reconciled to the world designer's, Quiet 3 shortened.

Changes from the concept packet (DES101 r5). The glow-range and split-surge rules are withdrawn from the baseline and kept as the labelled alternative. Power and signal lines are new, to give PM's "coil cannot select intake" a physical reason; the world designer reached the same separation independently. Holding, proximity and thinning are the world designer's terms, adopted. The siphon and the optional arc modules are new. Numbers are proposed throughout.

Asset check record. OpenGameArt FAQ read today: licence list and per-asset licensing as stated in section 14. Kenney: the assets listing page (kenney.nl/assets) shows no licence statement; the "Top-down Shooter" pack page (kenney.nl/assets/top-down-shooter) states "Creative Commons CC0" and 580 files. Both fetched read-only on 2026-09-06; suitability not assessed.

Open handoffs. World designer: a contradiction check of this draft against WLD102 r8, and any correction PM's routing ruling requires. Critic: REV102 on this draft. PM: the routing ruling the world designer requested (confirm D013 or reverse to the sight-limited model), whether the routing alternative goes to the owner as decision 3 either way, the standing of the External Critique page, and whether the enemy-art approval request should be raised now. The Design page header (211106) and the Glossary (86c1c4) already point here for rule details, so no page states the withdrawn glow-range rule as current.

PM report. Task DES102; artifact Design Document draft r2 (r1 d828a4 in history); no canonical decision changed; reasoning is written design against the cited revisions, no player data; risks are listed in section 16; next handoff is REV102 and the world designer's contradiction check; one PM request: rule on the routing model the world designer's r9 raised, since it decides section 4 and both scenes, and say whether the alternative still goes to the owner as a decision.