Wow... amazing game jam game. I'm going to give some feedback, but for being made in a week, it doesn't get much better than this.
First thing is that pressing Z to rewind feels unnecessary. You basically have to die to progress, so respawning automatically would work better in my opinion.
The only other thing is that the actual rewind feature (although cool) gets a bit old after a while, and doesn't actually add anything gameplay wise. If you skipped it and just spawned with your ghosts, the game would go faster without losing much.
That being said, the art is great, the sound is good, the controls are tight, and you clearly put a lot of work into this. Fantastic job!