I really enjoyed it! Great level design, I loved seeing parts of the level interconnect - even if the levels here don't have that much sense of scale. I can imagine this being easily expandable with a few more levels. Also, the graphics were pretty nice! I wasn't a fan of the main character design, but all the effects and style easily made up for it.
Now for the flaws, which are nitpicks at most: when you are rewinding and press a button, the object that the button affects moves in forward motion, which is kind of unintuitive. Also, when rewinding, the turrets keep shooting forwards, which is kind of weird (you end up with one bullet going forwards and another going backwards at the same time). I know how hard this can be to implement, especially in a game jam, so I completely understand you not having done it: I'm just throwing ideas for a future version, if you want to do it. Something which may be easier to implement: I think it's kind of annoying that you can't interrupt the rewinding at will! You should have another button to resume forwards motion. OR, more interestingly, you should use that to your advantage! Have a level where you need to time a jump when you're in a rising platform or something, so that the inability to stop rewinding at any time turns into an interesting challenge for the player.
Overall: great game! I really enjoyed it. The list of flaws is huge because I'm terrible at explaining, if we went by importance it would be 95% praise and 5% criticism. Good job!