Great looking RPG game.
I'm no usually a fan of these kind of games as they are too slow for me, but it looks well made.
I got until the piano puzzle where it told me to play the major scales of C.
Now I don't know music theory and in my opinion you shouldn't have to look up stuff in a game, so I am not sure whether I missed a hint or something but if not then I would incorporate a hint there how to play the Major scales of C. Some sort of musical magazine could be left there for example.
Great job !