I love rythm games! nice work with this one, it's quite fun and good job creating the relationship with the theme.
My only recommendation would be to make it more obvious that there are 2 separate lines of keys, and the ones on top are the next ones coming after succesfully inputting the ones in the bottom, at first I thought that I had to input all both lines to advance and was confused by it.
In general great rythm game! congrats! :)