level select
Enter "8ODYS" as a code.

Invincibility
Enter "HPPYHPPY" as a code.

All weapons
Enter "RCKTSRDGLR" as a code.

Campaign mode bonus level
Enter "WRDRB" as a code to unlock the Boat Assault secret level after campaign mode is completed.

Brandon gang
Enter "NNKNHCKS" as a code.
Custom 1 gang
Enter "TRDDYBRRKS" as a code to unlock the Custom 1 gang (M2 Hydra tank) in multi-player mode.

Customized gangs
When you enter the "TRDDYBRRKS" code and "Custom Gang" appears at the bottom, you can actually type in letters and customize your own gangs. For example, if you enter "TRDDYBRRKS" and then enter "X", you get grenades, two Goliath tanks, 2 FLP-Es, and a Laser Tank. You can also type in various combinations to get various groups. For example, enter "SGG" for three Goliath tanks, an Inferno, and a Motortank.

Weapons power-up
Begin a game and collect at least fifteen of one weapon, except for grenades. Aim at an opponent, then press A + B to fire a powered-up version of that weapon. Note: Press A + B + Z when guided missiles are under your control to fire a blue laser.

Commit suicide
While playing the game, press C-Up + C-Down + C-Left + C-Right. This is especially useful if you have selected the wrong tank with the invincibility code activated.