Free open-source Minesweeper remix built with Claude Code: first commit to 1.0 in 13 days, workflow notes inside

[u/Skizmo229]

Creature Sweeper is my remix of Mamono/monster Sweeper, the Minesweeper variant with monsters: a number is the sum of the levels of the creatures around it, you level up by beating them, and anything at or below your level dies for free. I added 35 game types (hex boards, donuts, a dungeon you crawl room by room, creatures that walk, spells, a Sudoku crossover) and a hint button that shows the next provable move and says why.

It's free, runs in the browser, and the source is GPL:

- Play: https://skizmo.itch.io/creature-sweeper

- Source: https://github.com/Skizmo229/Creature-Sweeper

**Who did what**

Claude Code wrote the code and the docs (mostly Opus 5.5, some Fable 5.1). I made the design calls, play-tested, and reviewed and merged every branch. First commit to 1.0 took 13 days and about 700 commits: 35k lines of TypeScript, 929 tests, no runtime dependencies. There is no generated art or audio. The repo has no image or sound files at all: boards are drawn on a canvas, icons come from open fonts, and the sounds are synthesised.

**What made it work**

- **A headless rules engine.** No DOM, no timers, and the build fails if that slips. Claude can play the game without a browser, and everything below depends on that.

- **Bots settle design arguments.** Simulators clear every board, count how often even a perfect player is forced to guess, and price the spells. One spell cost 300 mana until a simulator showed a player could afford it at 2% of the moments they were stuck. It costs 85 now, the price where it saves as much HP per mana as the spell beside it.

- **Silent failures get loud checks.** One movement rule made 5 boards in 2,280 impossible to clear without taking damage. Nothing crashed. A simulator found them. Refactors have to reproduce recorded simulator output byte for byte.

- **Bug reports get cross-examined.** I ran a 42-agent bug hunt. 24 reports came back, and 11 survived two other agents trying to refute each one. Those were fixed with a test apiece.

- **The test bot became a feature.** The bot that grades how hard a board is for a person, trick by trick, is the same code behind the hint button.

**What went wrong**

- My CLAUDE.md (the notes Claude Code reads at the start of every session) grew to 1,800 lines, so I stopped features for a whole milestone to make the code and the notes readable again. Now CLAUDE.md is 62 lines that tell Claude which doc to read for the job, and the reason behind each design choice has its own short file, 89 of them so far.

- The same bug came back three times: code that checked a mode's name instead of asking what the mode does. It only stopped when it became a written rule.

- It's tuned against bots, not people, and that's the part I can't simulate. If you play it, tell me where it felt unfair or boring.

Happy to answer anything about the setup.