I think the other players summed it up pretty well with what could´ve been improved. I for once also had the problem that the piano seemed to be unresponsive on some of my tries to press the keys. But that might´ve been just my luck.
Otherwise a really solid game! I play a lot of point-and-click adventures and I am an avid fan of puzzle games, and I was super happy to find your entry after you commented on my own game. Thanks again for playing ♥).