You know what I want the plot for the game to be?
Rabies.
God Rabies.
Follow me on this here:
The guy you're playing has some sort of affliction that just makes him SO ANGRY because he's got this super migraine. Everything is a target because everything makes his migraine worse. So you get basic goals like "SMASH" or "BREAK THROUGH", and that is kept from being repetitive by introducing various game mechanics like your basic weakpoints for enemies and environmental hazards.
As you play, you do get some semblance of what seems like a story: the details are told through damage in the environment that the player can recognize as something his character might have done, or maybe a trinket of days before the mega rabies. There can be a few cut scenes of enemy generals, but for the most part it's all very mysterious and ultimately the player is just controlling death and mayhem incarnate with no apparent motive.
This, of course, will NOT be what the game is like, but I don't mind that at all. The game looks hilariously fun so far.