That's a really cool idea! I had a lot of fun but I couldn't get past level 7. The screen became blank and I could hear sounds but see nothing.
As for my thoughts, here they are:
1. There are problems with the jump and overall some problems with collision that I think it's really important to fix. They can be really frustrating at times.
2. The particle effects (especially for the jump) are a bit over the top, I think. I think you should consider toning down the amount a bit.
3. Maybe you could add some feedback for rewinding? Some sound or visual distortion? I think it would really add.
4. There was another thing that I thought about and can't remember... I will write another reply with it if I can remember it.