unsolvable without outside help
There was no reasonable way to figure out the part with the piano and a significant number of other parts of the game without the walkthrough. I don't know what goes on in the minds of programmers when they make parts in their games like those, that people can't figure out without being told outright. I guess you think that if people can't figure out parts of your games, it means that you are smart. It actually means the opposite. It means you are pretty clueless about how to make a puzzle & even about how thought processes work. Maybe part of the problem is that you don't think enough about the perspective of someone who didn't program the game.
The art, music & theme were good. The choice of controls for the hardware were good, but in-game, it was hard to figure out how to do more than a few things with them.
The game needs a solid 17+ age rating, not 16+.