I like the idea of your game. It is cool to have the same ability in portal but with rewinding instead of portals. The textures fit very well and I like the narrator voice. There were some issues which Blue Cactus Games described very well. Another thing that I would add is checkpoints which would make your game much more enjoyable. I would also add a sound for the rewind gun so that you get some better feedback if you shot and it´s not that quiet while playing. Something like fan rustle would also work. Overall a nice game which would deserve more ratings. Good Job!
I´ve submitted a local multiplayer game: https://itch.io/jam/brackeys-4/rate/722755. I would be happy to get your feedback on it. :-D
Edit: Just found a bug: You clip through your body while crouching: