In the latest Iwata Asks, not yet translated to English, we find out that staff from Mario Kart 7 were pulled over to other projects, such as Nintendogs + Cats, and Mario Kart 7 was nearly delayed past the holiday season. Luckily, Retro Studios, who already had worked on the Donkey Kong Country level in the game, pitched in to save the project. EAD worked on 16 new levels while Retro recreated 16 classic levels, saving the day and ensuring that the 3DS would have a full holiday lineup.
Retro Studios Stepped In To Save Mario Kart 7
November 27, 2011