Check this post on Joystiq:

http://feeds.joystiq.com/~r/weblogsinc/joystiq/~3/91677544/

Check this quote:

" In short, the single- and multi-player elements of the game are merged, so those heretofore mindless enemies -- yup, they're your fellow carbon-based mammals."

Now, that's kid of an interesting idea.  I picutre either playing as the Hero with actual smart enemies but otherwise being mostly like any other game, or putting yourself in the "bad guy peon" queue.  In this queue you would play different bad guys with their own moves/powers/weapons/whatever but ultimately far weaker than the Hero since in all games the hero must kill 343,999,777 weaker peons before he can get teh powar up win teh game!  You would play for a short deathmatch-ish time then wait in line until the system needs to spawn another bad guy, possibly jumping from game to game depending on a centralized server sending bad guys to whatever system they are needed.  A cool idea, and one more to add to my list if they bring out an Xbox360 with HDMI.