For those that have read the Scott Pilgrim comics, you'll be pleased to see Edgar Wright has somehow made the most beautifully literal translation of comic to film imaginable. For those that haven't, you'll be pleased to see Michael Cera and Jason Schwartzman duel with a flame katana and a pixel light saber (respectively).
I don't know if this is a "game changer," but I think it's at least a game alterer. Like when you play Monopoly with the house rule where you get the collected money people have been losing to the tax spaces when you land on Free Parking. That's this.
(Or see the visible sound effects in HD at The Apple Corporation Site, thanks to helpful tipster Carter.)