The turning animation was a nice detail.
Really ambitious game idea and you got pretty damn close to getting it to work. In it's current state, I was able to knock my past self off course a bit too easily, and some levels I didn't get to play because I accidentally killed myself too quickly (or it killed itself). I liked how the state of the level changed to make the platformer harder for the return trip on some levels. Good design, just needs some tightening up on the core gameplay.
Nice work!
*bug: Level 5's replay brings you to level 6.