Awesome
Kind of reminded me of the Super Smash Brothers games. I've tried few characters, but the one that I liked the most was the tankmen... especially his Fierce Attack when you picked up the AK-47 Power-Up.
Anyway, I really enjoyed this game. Some would want more fighting arenas, characters, moves or power-ups, but it must have been hard to make as it is. In my opinion, it was perfect like this.