If NSMB Wii taught us anything, it's that you shouldn't underestimate the potential of 2D platformers. This is just the title that Japan needs to help boost Wii hardware, not only in Japan, but worldlwide. I think this game will sell at least half of what NSMB Wii sold there, so maybe around 2 million, just in Japan. In the West I think it'll sell 6-8 million. This will be Nintendo's biggest holiday title, even bigger than Mario Sports Mix, Wii Party, Goldeneye, or Kirby.