A pretty decent game I'd say but I have some critiques:
First off you either need to make the screen size smaller or make it so you can go into full screen mode
The spawn rate is way to fast! You just click as frantically you can kill them all
The enemies also only go to one position and spawn from one position so it's not too hard to kill them off
However, Your shooting mechanics work great! I could shoot as fast as I wanted to without it bugging out! I also like the designs of the characters you used they were very nice looking! Keep it up!