Wii Fit. Well, fastest game to reach half a million copies sold, that is.
According to independent market research group GfK Retail and Technology Australia, the game has sold over 520,000 copies in its one year on sale. The only Wii game that has sold more is Wii Play at 569,000 copies. Mario Kart Wii has sold 328,000.
Wii Fit conquering one continent at a time.