Very good game
I really enjoyed this 30 minutes of playing it constantly without a break! It is really fun and challenging. It makes you play it again just to see what gun and what level you get next! Very nice graphics and I like the music! Game looks pretty! I love how game keeps you away from camping. I'd love to see it progress if that is your plan with this game. For 1 week it looks awesome!
These below are my opinions on the current game state. Things in the brackets are stuff that you could add/fix if you want to continue developing it "outside" of this game jam. If you are not planning to continue it, then you should focus on the rating rather then comments.
Gameplay : 9.3/10 (could use more features like power-ups and etc. Maybe adding stuff like seasons where the background changes per level)
Music: 8.8/10 (maybe some other tracks?)
Graphics: 8.5/10 (I wouldn't add nor change anything around graphics that much)
EXTRA: I'm liking those meme sounds effects you got there :D.