I'm playing with Claude Code to build an ASCII factorio-like. I first had it write code without much code supervision. It quickly added most of the core features you'd expect (save/load, options, debug, building, map generation, building, belts, crafting, smart belt placing, QoL). Then I started fixing minor bugs and each time it would break something eg. tweaking movement broke belts. So I prompted it to add Playwright automation. Then it wasn't able to write good quality tests and have them all pass, the test were full of sleep calls, etc...
So I looked at the code more closely and it was using the React frontend and useEffect instead of a proper game engine. It's also not great at following hook rules and understanding their timing in advance scenarios. So now I'm prompting it to use a proper tick based game engine and rebuilding the game up, doing code reviews. It's going 'slower' now, but it's going much better now.
My goal is to make a Show HN post when I have a good demo.