Successfully complete the game on the Normal or Hard difficulty to unlock New Game Plus mode. Pull out the Cryptographic Sequencer, then hold LB + RT and rotate the Right Analog-stick clockwise ten times to make Batman's head and all enemy head's larger.
If you entered the code correctly, you will hear a sound when you continue your game. At the main menu, press Left(2), Down(2), Left(2), Right, Up(2), Down to unlock an option to select any of the bonus costumes.
