I've been playing all day, they started selling it a day early over here The game is really fun, looks amazing, but there are a few things I hate.... 1) You can't change the control buttons, 2) there's too many baby characters and I'm missing some others, 3) Split screen with friends is vertical, so it's harder to see the curves in the track than with a horizontal split, and 4) I haven't found a way to reset the game if you want to start over and earn all the karts and characters from scratch.... Overal I'd give it an 8.5 to a 9 though, it's really fun, not too easy, looks spectacular, it's original, and there's a lot of possibilities!
Try deleting the save data from the main Wii U data management?
I went and redeemed the code on Club nintendo asap but then I read the terms and it says the code must be redeemed between 10am today to July. Like I think I did it too early, cus it's not even 1am.