Game · JavaScript

thaw

Twelve rooms, and a solver that proves every one.

An ice-sliding puzzle game. You slide until something stops you: snow, rock, or a crate you kicked into place. Slide a crate into water and it sinks into a snow tile you can stand on; cracked ice breaks behind whatever leaves it. Reach the hut in par for three stars. A breadth-first solver proves every room: the tests re-solve all twelve on every run and fail if a stated par is wrong or a level's crates aren't actually needed.

Language: JavaScript Released: v1.0.0, 2026-10-27 Licence: MIT

Play on itch.io View on GitHub Task pack All games

Par comes from the solver, never from a person.

Play it in the browser on itch.io or on GitHub Pages, or run it locally and verify the task pack:

npm start · npm test · npm run tasks

Walkthrough

The player slides across ice, kicks a crate into the water to make a bridge and reaches the hut. — Level 9, Ferry: kick a crate into the water, cross on the snow it leaves, reach the hut.

The level select screen: twelve rooms with star ratings. — Twelve rooms. Each new element arrives alone before the later rooms combine them.

An orange arrow beside the player suggests the next move; the HUD says hint used. — Task feat-01's reference solution: a hint computed by the solver from wherever the player stands.

Task pack

Three tasks in the shape used to evaluate AI agents on game development. Each has a brief written as it would arrive, acceptance criteria (input sequence, expected visual outcome, verifiable game state), a reference solution with root-cause notes, and an automated check against the real rules. A verifier proves every check fails on the starting state and passes on the solution, with the whole unit suite green.

Undo doesn't fix the ice

Bug · player report

The undo snapshot became a shallow spread that shares the tile array with the live game, so broken ice and filled water survive an undo.

Next level starts with a move made

Bug · QA ticket

Presses queued during the winning slide aren't cleared when a level starts, so they play on the next level (or after a restart).

Hints

Feature · producer request

Run the solver from the current state and show the next move; report dead ends; cap a hinted run at two stars. Touches the solver, session, scoring, UI and input.

Verified proof

19 unit tests: all twelve levels solved at their stated par and replayed through the rules, crates required where present, every rule, undo, the input queue and stars. All three task checks fail on their starting state and pass on their solution with the suite green. A headless browser smoke test plays all twelve rooms through key presses at par and tries a swipe, with no console errors.

How it is built

Pure rules, a pure session (levels, undo, stars, input queue, with time passed in) and a separate screen. Level 1 was built by hand; the rest were found by a solver-driven search that keeps only rooms whose shortest solution is long enough and uses the mechanic being taught, then picked and ordered by hand.

Honest limits

Twelve rooms. Tested in Chromium; Firefox and Safari use only standard canvas and WebAudio APIs but haven't been verified. Built without an engine.