I was super-excited last night. I inserted the disc into my Wii U, booted up the game and watched the opening cinematic. Then the game prompted me to put a Land Vehicle on the Portal of Power, and...nothing. I kept removing and putting my Barrel Blaster onto the Portal, and one of two things happened: either the game would start to register the vehicle three times in a row before losing the signal, or it simply wouldn't register at all.
Eventually, I managed to get to the introductory video for the Barrel Blaster, but just before it finished, a message appeared saying "Your Vehicle may be corrupted." It seemed to stay on the screen for a moment, but then it disappeared again. I removed it and put it back, and...nothing. It seems that it's a problem with the Vehicle rather than the Portal. Needless to say I'll probably need to return it and get a fresh copy.