This is a great game. I got a highscore of 5010.
A very tiny constructive critique, would be to try to get some SFX from the player when he jumps, SOR style. That would be amazing.
But I had fun, and I love the idea with your character selection. Audio was polished, visuals were polished, the health bars are Aesthetically pleasing to the old eye retinas.
The level design has a nice grimy feel. I would love to know what happens when I get to 99 kills, but I don't think I'm good enough to reach that.... Yet.