Interesting idea, but felt a little bare bones. Perhaps I was playing incorrectly, but the rounds seemed to take way too long. I was going for ~3 minutes and round 1 was only half done - I couldn't go on much more without just letting them go on until I could rage out and kill them.
Ingame art was simple but nice, but there didn't really seem to be a lot of consistency in art style between the game and the menus (and even just the menus with the menus).