Codes
During gameplay, use the Dreamcast Keyboard to type 'iwillcheat' to activate Cheat Mode. Now enter any of the following:

Code Effect
Allloot Add Everything to Inventory
bluestars Activate German Version of Game
funnyhead Big Head Mode
missionover Instant Mission Completion Without Saving
gamefail Instant Mission Failure Without Saving
showtheend Skip to End Sequence
goodhealth Full Health
openalldoor Open All Doors
playercoords Display Player Coordinates
debugdrawwire Wireframe Mode
enemyf Cycle Through All Enemies (Front)
enemyb Cycle Through All Enemies (Behind)
killthemall Kill All
cantdie All Soldiers Invincible
resurrection Resurrect Fallen Comrades

Cheat mode
Enter RVL at the name entry screen and keep the "L" highlighted for the next letter. If done correctly, your name will appear as RVLL with the second "L" still flashing. Press Start to delete your name and press B to return to the main screen. "All missions" and more options will now be available. Press Start to pause game play during a mission to display a menu with a variety of cheat options.