Threat

The astronaut moves through the Entrance Sector while the approaching crowd changes: fragile bodies, slow obstacles, quicker pursuers, then a large fragile crowd and a quieter interval. The Promenade, Waiting Areas and Cafeteria share this sequence. Moving between them changes the available routes, while the encounter clock continues.

Zones and time

The Entrance Sector is one zone. Later zones will have their own enemies, rules, schedules and higher baseline difficulty; they replace Vampire Survivors' separate stages in this game's structure. Within Entrance, room identity and distance from the Dock add no numerical difficulty multiplier. The Owner Brief records the direction and trial authorization.

Threat gains one second per running second that the living astronaut spends in dynamic unsafe rooms. Safe and static unsafe rooms stop its advance; ordinary world time and oxygen continue. Pausing stops it. Returning or dying retains the final value; a new departure resets it. Saving and loading add no time. Doors and room crossings grant no reset or new grace. Only the player's active connected dynamic combat area receives new enemies.

Safe rooms exclude enemy spawning, movement and attacks into them. Static unsafe encounters retain their separate rules. Bosses belong to specific rooms and are not scheduled by Threat.

Entrance schedule

The first ordinary spawn opportunity is at three Threat seconds, once per departure. Later opportunities follow the refill rate below. Rates are constant within each row. New-spawn probabilities are independent choices, not forced ratios among surviving enemies.

At 9:00 the last three rows repeat: mixed crowd, large fragile crowd, reduced reinforcements. At 9:00 use the 6:00 row, at 10:00 the 7:00 row, at 11:00 the 8:00 row, then repeat. The actual clock never rewinds. There is no further stat escalation, repeated grace or restoration of defeated enemies.

Combat And Enemy Roster owns the effective fixed role cards, hit displacement, melee protection and presentation. These replace the earlier continuous HP curve and speed/damage multipliers for new Entrance enemies. An existing enemy keeps its saved birth HP, speed and damage; a phase change does not heal it or change its type.

Local crowd and connected cap

The nearby target counts living dynamic enemies reachable within 30 metres of navigable path through the active connected combat area, including around corners and through open doors. It is an admission target, not a guaranteed onscreen count. An enemy's own footprint is used for its route, including full wall clearance at furniture detours; a gap narrower than that body is not a shortcut. Camera rotation does not change the count.

The hard admission cap is 120 living dynamic enemies in the active connected area, including distant bodies and enemies with lethal shots in flight. Corpses do not count. Open traversable dynamic-to-dynamic doors join an area; safe/static rooms, locked doors and unbuilt destinations do not connect it. Count retained bodies immediately when areas reconnect. A joined population may already exceed 120; new admissions then wait until below the cap. This is a connected-area ceiling, not a promise of 120 total across disconnected parts of the sector.

Each spawn opportunity requires a population below both limits and a legal position. A failed or capped opportunity is spent, with no later catch-up burst. A lower target stops reinforcements while too many enemies remain; it does not erase survivors. A strong build may clear bodies faster than refill and keep the fight below target. Equipment, health and kill speed do not make the director retaliate with stronger or faster replacements.

Placement and abandoned enemies

New enemies need clear floor, a route within the active area, at least eight metres from both the game and controller positions of the astronaut, and at most 30 metres of navigable route to the player. Placement uses the common largest current footprint before rolling a role. Prefer legal floor near the unseen camera boundary, within the existing six-metre search band. Use the current viewport test with its margin: a wall hiding an onscreen point does not make it an offscreen spawn point.

There is no visible farthest-point fallback. If unseen legal floor is unavailable, discard the opportunity. This can suppress arrivals even with space under both population limits. Existing enemies may walk into view through a doorway. Numerical sampling enforces the placement rules; it does not guarantee a successful spawn whenever some theoretically valid point exists.

After finding a legal slot, choose the role using a separate saved random stream. Target, cap and placement failures consume no role draw. Position sampling and reward randomness have their own streams. New bodies are alerted and walk toward the player.

An ordinary dynamic body that remains unseen and beyond the nearby route boundary for 15 active Threat seconds is removed without a combat kill or corpse. No reachable path also counts as distant inside the active area. Visibility, proximity or an active attack/projectile/control interaction resets that removal timer. Safe/static time, pause time and time outside the active connected area freeze it. Reevaluate distance and visibility on resumption. Nearby and visible survivors persist across phase and room changes. A replacement must pass normal admission and refill rules; it is never teleported beside the player.

Saved departures

Threat, partial spawn progress, all three random streams, enemy birth stats, remote-removal progress and short combat-control timers survive reload. Earlier Threat saves preserve their time, property, existing enemies and reward ledger; the new role stream is initialized deterministically without advancing the older streams. New births follow this schedule. A fresh departure starts the new encounter sequence consistently.

An active save from before Threat still finishes its old finite encounters and switches at the next departure. No new-game reset is required. Static/legacy encounters retain their prior combat-response rules; the new contact/displacement rules belong to the ordinary dynamic Entrance roles.

Chests

Every 30 Threat seconds earns one chest event: 30, 60, 90, 120 and onward. Events are global to the departure. Changing rooms, killing enemies or loading cannot repeat one. All three current dynamic rooms can receive them, including the Cafeteria.

Each event reserves one remaining card from the shared chest deck, without choosing it yet. Pending and unopened chests hold reservations. If no unreserved card remains, that event creates nothing and is not banked for later. There is no separate twelve-chest limit: today's twelve-card deck happens to commit all its rewards by six minutes. Future deck expansion is separate work.

A chest appears on clear reachable floor in the current dynamic room, two to five metres walking distance away, with its full footprint clear of actors and furniture and at least one metre clear of doorway openings. Prefer the closest legal place to two metres. It never pushes anyone aside or needs a cleared fight. A brief notice and the chest's existing light mark its appearance.

Placement preserves previously reachable open exits and a reachable approach to the new chest. This is an implementation safeguard discovered during the first trial: repeated near-player rewards must not form a sealed ring around a stationary astronaut. The solid collider is present immediately, before the next movement step.

If placement is blocked, keep the earned event and reservation. Retry the oldest pending reward each additional Threat second and upon entering a dynamic room. Pending rewards follow the astronaut until placed. Placed chests stay where they appeared.

Rarity is rolled once when the threshold is crossed: 90% ordinary, 9% rare, 1% extra rare. These come from a 10% rare-or-better chance and a 10% extra-rare chance within that group. The effective probabilities and result are saved, so movement, loading, opening and future gear changes cannot reroll an earned chest. Future gear modifiers have a place to supply these probabilities; no modifier formula or rarity effect has been added. All grades currently draw one item from the same deck with its normal rules.

E opens the chest and draws the next shuffled card, consuming its reservation exactly once. Opening order determines the items. A full pack leaves the same drawn item in the chest. Reopening never redraws. Reserved chests can still open after all remaining cards are reserved. Static chests remain independent; other dynamic chest sources also respect reservations.

At the next departure, unplaced and unopened rewards expire, the counter and event ledger restart, and the configured deck is reshuffled. Drawn items left in opened containers remain accessible at their saved locations and never consume the new deck. Ordinary static-chest property rules remain.

Open questions

Verification for this trial: all 354 Core and 90 Unity tests pass, including placement with the real furniture and camera in each Entrance room at two camera angles. The three role appearances were inspected in all three rooms at normal camera distance. These checks establish rule behavior and rendering, not difficulty, sustained-density performance or moving-player feel.

• This is an implemented first trial with initial tuning. Moving-player feel, long visits, crowd readability and performance at sustained density need play feedback.
• The stationary two-starting-pistol run is a diagnostic, not a target for defeat at two to three minutes. Earlier measurements belong to older tuning and are not current balance evidence.
• If offscreen/route constraints suppress pressure widely, compare a clearly signalled visible arrival with a more distant route-fed arrival explicitly.
• Future zone transitions need their own clock and revisit policy. Passing rushes and additional ordinary roles are later work.