Really cool how you've changed the enemies to all be different, the massive grey ones scared me. The power ups are good,. My only downside is there doesn't seem like an incentive to die, I can play the game like a shooter and if I die then it's a bonus, but I never felt like I needed to get myself killed to progress. Maybe if there were specific rounds such as 1 grey guy who you needed x powerup for, and this was visualised somehow, that would add to the effect.
Also i love how the instructions are on the wall in front of spawn. Thats sweet