Yep, I literally built this last night with Opus 4.5 after my wife and I challenged each other to a typing competition. I gave it direction and feedback but it wrote all the actual code. Wasn't a one shot (maybe 3-4 shot) but didn't really have to think about it all that hard.

https://chronick.github.io/typing-arena/

With another more substantial personal project (Eurorack module firmware, almost ready to release), I set up Claude Code to act as a design assistant, where I'd give it feedback on current implementation, and it would go through several rounds of design/review/design/review until I honed it down. It had several good ideas that I wouldn't have thought of otherwise (or at least would have taken me much longer to do).

Really excited to do some other projects after this one is done.