Hidden mode:
     At  the  mode selection screen, press Right, Down, Right, Square,
Up,  Square,  Square,  Triangle,  Down,  Right,  Down,  Right, Square,
Triangle.

Mirror mode:
     At  the  mode  selection screen, press Left, Left, Right, Square,
Down, Down, Up, Triangle, Up, Right, Down, Up, Left, Down, Square.

First person view:
     At  the  mode selection screen, press Up, Up, Up, Up, Down, Down,
Down, Down.

Fast mode:
     At  the  mode selection screen, press Down, Triangle, Up, Square,
Triangle, Down, Right, Down, Right, Square, Triangle.

Romantic mode:
     At  the  mode selection screen, press Left, Right, Right, Square,
Triangle.

Night mode:
     At  the  mode  selection screen, press Up, Right, Down, Left, Up,
Square, Triangle.

No crosshair:
     At the mode selection screen, press Right, Right, Right, Square.

No scope:
     At  the  mode selection screen, press Right, Down, Right, Square,
Right, Down, Right, Square.

No enemy cursor:
     At  the  mode selection screen, press Right, Right, Right, Right,
Left, Down, Up, Right.

Unlimited time:
     Pause  the  game in arcade mode and press Square, Square, Square,
Circle, X, R1, R2, L2, L1, Triangle, Select.

Exchange ? of life for 5 seconds:
     Pause the game in arcade mode and press Up, Up, Down, Down, Left,
Right, Left, Right, X, Circle.

Exchange 5 seconds for ? of life:
     Pause  the  game in arcade mode and press Circle, X, Right, Left,
Right, Left, Down, Down, Up, Up.

Extra options:
     Beat  the game under any difficulty setting to unlock a real time
window and up to 8 health in the options menu. Beat the game more than
twice  under  any  difficulty  level to unlock infinite credits in the
credit section of the options menu and +30 in the time limit section.

Mouse Aiming:
     You  can use an USB mouse for aiming and left and right click for
shooting.