The game was really fun and i think it has a lot of potential to be explored for a full version release. I think a mouse aim would be better and more intuitive, since then you would be able to keep walking in one direction and shoot to the other. Another thing that would be nice is to have the bullet crossing the enemies instead of stopping when hitting them, it would add the possibility for slashing multiple enemies at once and to finish them faster as you master the mechanics of shooting/rewinding.
Other than that i really enjoyed the game, it is nice and fun, hope you keep working on the project!