I created a 3D moon rover survey game with Opus 5.

No engine, no build step, nothing to `npm install`. One WebGL2 context, a vendored copy of three.js, \~6,300 lines of JavaScript, and regolith that keeps every rut you cut into it — because the wheels and the shader read the same height field. The whole thing: physics, renderer, terrain, lore, sound design, interface. It started as one prompt to Claude Code (Opus 5, ultracode): > That prompt produced a playable build. It did not produce this one. Everything since came from rounds of "fixes": steering inverted, wheels floating off the chassis, a HUD covering half a phone screen, a settings panel that had been collapsing to a 2px strip since the first commit. No design doc, ever. **What it is.** Five-mission campaign plus free survey. Twelve codex entries, nine sample types, and a station that stopped answering 214 days ago. Desktop, phones and tablets, it needs a browser from 2023 or later, because with no bundler it leans on native import maps. **How it's made.** Every…