There's a pic on there of a dude with a Wii remote and nunchuk, but he could be playing Mario Kart.
The rumor, from a few years ago I think, was that Spector was developing a "Mario Killer" Mickey Mouse platformer for Wii. And everything since then has pointed in that direction. But things change, and things can really change when rumors hang around for years with no announcements.
So while I'd say there's a 90% probability of it being a Wii game, we can't assume anything.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.







