Nice little game!
Audio I liked the music but I missed some sound effects, it makes a game more satisfying to play and can have a lot of impact.
Gameplay feels a little bit weird. It looks like every thing else is moving but it should feel like you are moving, this is because your player is always centered. Maybe add a bit of delay to the camera when moving. Also the gun doesn't point to your mouse. Further more gun shots feel good. The enemies also feel not that smart. They damage you once and that's it, maybe it's just a bug.
User Interface feels a little bit chaotic. But maybe this is because of the theme. The button are very big but don't stand out that much. Also adding a pauze menu is a handy feature.
Graphics are a very minemalistic but they don't need to be more for a game jam. Like the particle effects.
Theme fits totally into your game : D.
Sorry for all this critiques it doens't mean that you made a bad game. You can improve your game and make it even better. Overall a good job. If you want to ask a question feel free to do!