I really liked the shift on the normal approach to the theme. It's simple but great, and those are a lot of levels.
Some little details: the idle animation was a bit too quick, it didn't seem that natural, I felt the player speed a bit too slow, and it would've been nice to have something like "R" to restart, it was a bit annoying to have to press P (when my brain always defaults to esc, but that kicks you off if you're on fullscreen) and then restart.
The art is very nice as well as the audio, well done!