Level skip:
Press Start to pause game play, then press Up, Down, Left, Right, Right, Left,
Circle.
Level select:
Save the game and return to the main menu. Select the "Resume Game" option, then
highlight the previously saved game and press Up, Down(2), Up, Left, Up, Right,
Down.
Invincibility:
Press Start to pause game play, then press Square, Circle, Left, Right, Circle,
Square.
All ammunition:
Press Start to pause game play, then press Left, Right, Circle(3), Right, Left.
Firewire multi-player mode:
Note: This trick requires a four port Firewire PC hub. Use Firewire cables to
connect the iLink port of one to three more PlayStation2 consoles to the hub.
Press Start to pause game play in two player multi-player mode and press Left,
Circle, Left, Right, Square, Right. Have all players press Start at the waiting
screen.
USB multi-player mode:
Note: This trick requires a USB keyboard and USB mouse. Change the controller
configuration to set the keyboard to player three and the mouse to player four.
The game can now by played with four players.
Fatboy Mutator:
Press Circle(3), Up, Down(2), Up, Circle(3) at the main menu. Select
multi-player mode and choose the Fatboy Mutator. Get killed to have the new
Mutator get thinner. Get a kill to have the Mutator get bigger.
Stealth Mutator:
Press Square(2), Circle(2), Square(2), Circle(2) at the main menu. Select
multi-player mode and choose the Stealth Mutator.