In the past we've seen films with multiple endings, a la Clue. We've also seen films where the audience votes on a fate for the villain, as in William Castle's Mr. Sardonicus. However, I've never heard of a film with an interactive video game ending. In fact, I can't even wrap my brain around how that would work.
The film's title is a reference to the villain of a video game created by Shah Rukh Khan's character, a video game programmer. According to the scuttlebutt, in the film, the video game begins coming to life, and SRK becomes the hero, also known as G.One. Supposedly, for the climax the audience would be able to play the Ra. One game from their seats, I'm not sure how exactly, but it is certainly a novel idea. Could be fun if they make it workable somehow. They've got several months before the projected release and SRK just finished his portion of the shooting over the weekend, so let's see where this goes.