I really like the music! Strange you didn't choose to use arrow keys and WASD though for 2 player controls. It probably would have worked better with 2 hands on a keyboard.
Also, having your shadow bar/amount thing increase only on the ground feels like a shame for a map with that much verticality. it encourages just running back and forth on the ground instead of jumping around which is arguably more fun.
The rewind mechanic is well done, the gameplay is fun, and the music and visuals work together nicely! Overall, great entry.