I'm loving the puzzles! Reminds so much of an open-source puzzle game collection I install on every Linux distro I use, except this has better presentation.
I will note that I think puzzle 3 might have two solutions, but only one is accepted. Five seems to have even more solutions.
After enough time, the puzzle-solving music loop does get a little grating, but that is definitely the product of jam crunch preventing a longer track.
Would be really neat to build out algorithmic puzzle generation, but that might be beyond the GameBoy's specs.