Alternatively, you could have downloaded an existing one. What you did is just a roundabout way of acquiring one of the many WASM Rust GB emulators in the training set. Except it probably now has several problems from reconstruction. You didn't learn anything new from the process. It's just wasteful in several ways.

Likely because all of the external docs were already in its training set.

Yes, this project was made in around 15 hours of Codex.