Entered at Difficulty Select Screen, When done correctly "Code Accepted" will sound.

Code - Effect

Left Left Right L1 R2 Left Left Right - Amazon Boss Fight
L1 L1 L2 Square Square Circle R1 R2 - Amazon Level Complete
L1 Left L2 Right Square Square Circle Circle - Anarctica Boss Fight
R1 R1 R2 L2 L1 L1 R1 R1 - Anarctica Level Complete
L2 Left Right Right Left L2 L2 L2 - Mid Atlantic Boss Fight
Right Right Square R1 R2 Circle Left Left - Starship Boss Fight