Yeah, the game is great, really fun! For me personally the funniest part was how narrator yell their names! I have no idea how you did it, I used TTS for my game, but, it sounds just normal. Did you use video model to make those yells?
Talking seriously if have any connection to a sumo, or martial arts in general you gotta do some rock-scissors-paper mechanic. I mean in sumo you eather push your opponent out of ring or you meke him fall. If you charge too hard, the opponent just steps to the side and you break out of the circle yourself. Also there are throws.
Maybe do something like:
Dodge beats Charge
Throw beats Dodge
Charge beats Throw
That's not final, just brainstorm. Ah also I sence you were inspired by the jams' promo image, is that so? I mean you made a whole game in weekend, I remember that.