Nice game!
I have some sugestion
1. Game screen its very small, dont use a fixed size for the game, use a auto scale screen size.
2. Add a range to weapon, i just stay by side of the water, and didnt move so much during gamplay, just press and hold click, while aim the enemies.
3. Add a better feedback when enemies got hit, like a knockdown, ou damage text poping
But i had some fun playing, thanks for your game!
Nice entry and good lock!