Fun concept, and nicely executed! I thought the visuals were pretty good and the player character was very nicely drawn :) I thought some music would have really helped with setting the atmosphere though.
Overall nice work!
As I mentioned in my first comment, I think some music would really help with setting the atmosphere for the game and make the player more immersed. Other than that I did get confused at first with the shooting controls, it says on the game page to use left mouse button however it's the right mouse button that actually shoots. Thought I'd let you know!