The game has a great concept to it! A few things to point out:
I think it was level 5 or 6? The room with the 3 falling platforms at the right side. When I die, the screen goes to black, but does not fade back in. I can hear my character moving via SFX but the screen simply stays black.
The player seems to get stuck on the ramps going up and it's hard to control things while making them rewind, I would suggest making a more curved response to the rewind objects so you can follow them with your mouse, or just click and need to hold without following.
I loved the layout of the levels though, very good engagement style tutorial!
Overall, you have a good game!