It is, naturally, a little difficult to come up with a video game idea for Final Fantasy, since Final Fantasy is, well, a series of video games. The solution is to come up with something drastically different. The games in the series are linear, story-oriented role-playing games, in which the player often has to do little other than tap the X button at various points.
This game is rather different. The game would make use of the Nintendo Revolution controller, which is drastically different to other gaming devices out today, and would be based on the box office disaster, "Final Fantasy: The Spirits Within", which is as drastically different from the games as you can get. The game would involve the player having to make his or her way through various environments blasting Phantoms with the motion-sensing controller. Phantoms would come at the player from every conceivable direction, but only be visible if the player has thrown the special energy grenades.
Also, the controller will have an additional attachment specifically for this game; two small straps that cross over the player's chest. When attacked by a phantom, vibrations will really let the player know he/she's been hit! Between that and the realistic shooting aspect, this is sure to be one Final Fantasy experience you won't easily forget!