I didnt catch if this would be possible (besides over airplay) if anyone did I would love to know.
iOS games are designed for the touch screen on your phone/pod/pad.
the whole user interaction is different, So highly doubtful they would just work.
I was more so thinking games that already have mfi controller support (since i believe the tv will be able to connect to those).
Ray Wenderlich got "Zombie Conga" running in the tvOS simulator in 10 minutes:
http://www.raywenderlich.com/114313/tvos-initial-impressions