The four archetypes

The four archetypes

One 15 × 9 integer tile sim, one action alphabet, one scoring formula, one renderer. Each archetype contributes exactly one generator and one physics hook — that is the whole budget, and it is why there are four and not sixteen.

They are the four decision shapes the Procgen suite is built out of: search a topology, evade a pursuer, commit to a jump you cannot take back, and reshape the terrain you are standing in.

maze — search a topology

A perfect maze carved by an iterative backtracker on the interior's 7 × 4 odd lattice (lattice cell (i, j) is tile (1 + 2i, 1 + 2j)), with braidCount dead ends knocked out to make loops. Four gems sit on the lattice cells farthest from the start and the locked exit on the farthest of all, so every level is a real traverse.

• Physics hook: none. No gravity, no hazards, nothing that moves but the cog.
• X is a wait. A maze plan therefore always runs all six frames — the danger interrupt can never fire.
• braidCount: easy 8, standard 4, hard 1. Fewer braids means fewer shortcuts and longer routes.

chaser — evade a pursuer

An open room with pillarCount scattered 1 × 1 pillars, eight pellets, a locked exit and hunterCount hunters.

• Physics hook: each hunter takes one step along a shortest path to the cog, ties broken in the fixed order L, R, U, D — except on frames where frame mod 3 == 0, where hunters do not move. The cog is therefore strictly faster: three cog steps per two hunter steps.
• X is a dash: two tiles in last_dir when both are passable, then a four-frame cooldown during which X is a wait.
• A hunter sharing the cog's cell kills it, cause caught.
• pillarCount / hunterCount: easy 6/1, standard 10/2, hard 14/3.

climber — commit to a jump

Three walkable tiers at y ∈ {7, 4, 1}, each carried by a band of Platform beneath it (the bottom wall row, y = 5 and y = 2) and each with a tile of empty headroom above it. Ladders join the tiers; the lower band carries one or two gaps of at most two tiles, which are both the pit and the reason the jump exists.

• Physics hook: gravity on the cog. With jumpFuel > 0 the cog rises one tile per frame if the cell above is not solid; otherwise, unsupported, it falls one tile per frame and fallDepth grows. Landing resets fallDepth; fallDepth > fallLethal (4) kills, cause fell.
• X is a jump: jumpFuel = 2. Horizontal moves are legal in mid-air, which is what carries the cog across a gap — face the way you are going, X, then the horizontal moves.
• U / D move only on a Ladder (the cog is on one, or the target is one).
• A Spike kills, cause spiked. spikeCount: easy 1, standard 3, hard 5.

miner — reshape the terrain

The interior filled with Dirt, bedrockPct of it replaced by bedrock veins, four gems buried in it, boulderCount boulders resting on something, and the locked exit in the far corner.

• Physics hook: the falling scan, in the fixed order bottom row to top row, left to right — any Boulder or Gem with Empty directly below it moves down one tile and is marked falling; a marked entity that can no longer fall is unmarked. One tile per entity per frame.
• X digs the Dirt tile in last_dir without moving. A Dirt target is dug and entered in the same frame by a plain direction; a Boulder target is pushed one tile when the move is horizontal and the cell beyond is Empty, otherwise the move is blocked.
• A falling boulder entering the cog's cell kills it, cause crushed. A boulder resting on the cog does not.
• boulderCount / bedrockPct: easy 3/6 %, standard 6/10 %, hard 9/14 %.

What is deferred, and why

Twelve of Procgen's sixteen games are out of scope for v1, and each needs an engine this repo does not have: starpilot and plunder are scrolling shooters with projectiles and continuous motion; bigfish is a size-ordered ecology; bossfight is a boss state machine with phases; caveflyer and fruitbot need continuous flight; heist needs a key/lock graph on top of the maze. Four archetypes on one tile sim is what v1 can build and prove; adding a fifth engine is a second design note, not a switch.