Seems to be a random $10 discount on Tekken Tag for Wii-U preorder. It has some exclusive modes and Nintendo-themed costumes. I also noticed a Nintendo Network logo on the boxart, so I assume there's some kind of online play:
http://www.amazon.com/Tekken-Tag-To...sr=8-1&keywords=tekken+tag+tournament+2+wii+u
http://www.amazon.com/Tekken-Tag-To...sr=8-1&keywords=tekken+tag+tournament+2+wii+u