I used Claude Code to turn a 1989 DOS game I played as a kid into a relativity sim

Play it: [https://gravwars.com](https://gravwars.com) (free, no account, phone or computer) Gravity Wars is a two-player artillery game in curved spacetime. You take turns firing missiles past planets, stars and black holes, and gravity bends every shot. It started as a remake of a public-domain 1989 DOS game (by Sohrab Ismail-Beigi) and grew into a small relativity sim: orbits precess near black holes, black holes are ray-traced with lensing, and missiles feel time dilation. Almost all of the code was written by Claude Code, with me playing, testing and deciding what to build next. HOW IT'S BUILT • Claude Code in the desktop app, over many sessions. A roadmap folder and a [CLAUDE.md](http://CLAUDE.md) in the repo hold the plan and the rules, so each new session picks up where the last one stopped. • Plain JavaScript. No frameworks, no npm packages, no build step. A small Python script bundles the game into one HTML file. • WebGL shaders draw the universe and ray-trace the…