I registered just to give you a comment, I like the game a lot,
I would love to see more levels,
I personally like this art style (pixels) and loved the background music, t he boss was easier, I never understood music notes, and this game presented itself as a small learning course more and as game, I was reminded with the quote "games are challenges that a player should learn a skill to accomplish" and when I finished this challenge I learned how to read notes.