I really liked the fact you had different shooting sounds. The Graphics were nice too. The Enemy exploding with some Particles also was a nice touch. Here are some things i would improve: Sometimes i got a bit lost were i am when rewinding, you should probably put an arrow or something over the Player when the Rewind happens. You probably didnt have time for that, but more enemy types would have made the game way much better. Some music was missing too. I think this looks like a neat concept / prototype you could expand on. Nice job.