The graphics and music worked well together, it fits theme, and the game was pretty fun!
With that said, the difficulty curve is wayyyyyyyyyyyyyyy too steep, and like others have said, the game needed to be a lot easier. Additionally, I found myself having to make a lot of pixel-perfect jumps, which isn't really a situation you want to throw the player into. Instead, I would try and focus those portions more on the puzzle side, as opposed to hitting the button at the perfect moment.
On top of all this, the majority of jammers made almost the same game (two characters controlled by the same keys).
Regardless, this was very well executed, and was fun to play :)