It took me a bit to realize one needs more than memory to play this puzzle. Once approached with scientific rigor, ie a pencil and paper, it’s easy to solve. But very satisfying.
Two things I would do, if you’re going to continue polishing this: Animation for the hero, and a longer background song. The song is great, very NES, but one plays for long enough that it feels repetitive.
Overall, this is a real gem!