Pause the game and select the "Cheats" option on the menu. Select "Enter Cheat", then enter one of the following codes to activate the corresponding cheat function:

Cheat mode

Enter "GOLDENPIE" as a code to enable all cheats. -From: DpthChrgeX.com

Level select

Enter "SKIPPY" as a code. -From: DpthChrgeX.com

Invincibility

Enter "GODLY" as a code. -From: DpthChrgeX.com

All weapons

Enter "LOADED" as a code. -From: DpthChrgeX.com

Infinite ammunition

Enter "SORTED" as a code. -From: DpthChrgeX.com

Pen and ink mode

Enter "SKETCHY" as a code. This allows the game to be played without any texture mapped polygons, which gives it a hand drawn appearance.

Fast running

Enter "SONIC" as a code. This allows running to be done at twice normal speed.

Female Trooper in multi-player mode

Enter "GODDESS" as a code. Note: Only one multi-player mode character code may be used at a time. -From: DpthChrgeX.com

Hive Guard in multi-player mode

Enter "LEGGY" as a code. Note: Only one multi-player mode character code may be used at a time. -From: DpthChrgeX.com

Volcano Guard in multi-player mode

Enter "RUBBER" as a code. Note: Only one multi-player mode character code may be used at a time. -From: DpthChrgeX.com

Egypt Fodder in multi-player mode

Enter "CLAW" as a code. Note: Only one multi-player mode character code may be used at a time. -From: DpthChrgeX.com

Hive Fodder in multi-player mode

Enter "UGLY" as a code. Note: Only one multi-player mode character code may be used at a time. -From: DpthChrgeX.com