At the "X START" screen, hold L1 + R1 and press Up, Down, Right, Left, Circle, Triangle to unlock the Emma Frost costumes.
At the "X START" screen, hold L1 + R1 and press Down, Right, Up, Left, Triangle, Circle to unlock the Juggernaut costumes.
Successfully complete the game on the X-Treme difficulty. An arena mini-game will begin during the credits. Defeat 200 enemies before the credits end to unlock the Vintage costume.