This code unlocks all story levels, all characters and will give 9999 credits to use in the store (The code can be re-used to get more credits after spending them).

Xbox: Hold LB + RB and enter: Up Down Right Left X X Y Y
Nintendo: Hold L + R and enter: Up Down Right Left Y Y X X
Playstation: Hold L1 + R1 and enter: Up Down Right Left Square Square Triangle Triangle