Overall it's a REALLY good game for being made in a week! Sound design is really good, guns are satisfying to shoot, player works fine...
I see 4 problems:
-Rewind is... not important at all? I feel like this game would be even better without it, feels like it was a struggle to put it here
-As someone said, an end to the game, i guess it's an endless run to see how much score you get, but i feel like this game would have been better with some type of ending.
-More types of enemies would have been perfect, i know, its a gamejam, but for the future maybe? :P
-This is just my problem, but sometimes i cant see the ammo and health bars, i am bad with colors, so sometimes i couldnt see them, maybe a change of colors or making them more noticable...
Overall, great job!