It's interesting, isn't it? On the one hand the game is quite impressive. Although it doesn't have anything particularly novel (and it shouldn't, given the prompt), it still would have taken me several days, probably a week, working nonstop. On the other hand, there's plenty of paper cuts.

I think these subtle issues are just harder to provide a "harness" for, like a compiler or rigorous test suite that lets the LLM converge toward a good (if sometimes inelegant) solution. Probably a finer-tuned QA agent would have changed the final result.