Surprisingly a fun game!! I like the gameplay a lot, the visuals were okay too, Here's how you could improve this game in the future if you decide to work on it.
1 -> The bigger enemies should have more health.
2-> The map is very open, so adding some objects like trees and houses would be cool
3-> Guns, lots of guns. Currently you only have a pistol, which I can understand is because of the time constraint so i am not lowering my rating because of what is not in the game.
4 -> Better visuals, I dont mean they are bad, but they can be better.
Overall, I will say that this game is a great submission. It works, and its fun. Well done!