"This is no different than the basic story of Melee...and pays tribute to children playing with toys. A simple elegant system to allow Nintendo to bring their mascots to fight, but without having them truly fight. They are toys."
Seems more like they are slaves this time around...From the screenshots, I can gather this:
1) Mario and Kirby forced to fight
2) Mario wins and Kirby turns back into a trophy
3) Mario saves Kirby from his trophy state and they become friends
4) Bad guy controlling the trophies doesn't like that and comes down to play
With the fact that a "deeper" story seems to happening, it'd be really neat if all the battles to unlock characters had a tiny bit more dramatization to them (like Kirby running through the woods, then Metaknight jumps down, tosses Kirby a sword, and they fight...If you win, you get Metaknight, etc...)