I'm not sure where or how this fits the theme... I played to the win screen and never found how to rewind.

I would recommend stating controls at some point, at least for how to activate the rewind effect.

You wasted time on menus. It had nothing to do with the theme.

You don't need menus in a game jam. Also, the health of enemies is far to high or their hitbox is messed up idk. The bullets come out of my stomach that can't be right, can it? There also was no audio and the controlls fealt slow.

If this is your first first-person-shooter it is a solid start tho.