These built in codes only work in single player games. To activate cheats enter them into a chat box inside the game:

Teamgod: Team God Mode
Avatargod: Player God Mode
Stumpy: Stumpy Mode On
ClodHopper: Enlarges Player's Feet and Hands
MegaNoggin: Mega Head Mode
BigNoggin Big Head Mode
5FingerDiscount: Refill Ammo
NoBrainer: Turns AI Off
Debugkeys: Debug Keys Enabled
SilentButDeadly: Makes players "FART"
FastActionResponseTeam: ?
TurnPunchKick: Changes Players from 3D to 2D
1-900: Heavy Breathing
Explore: Victory Conditions On/Off


When entering debugkeys, press F10 to enter debug mode. These are the keys that work in debug mode.

A- Artifial Intelligence On/Off
B- Brings back to normal view
F-saves current co-ordinates to sherman.log
O-zoom in from F1 view
M- Freezes you, most likely AI turned off for just YOU not teamates
P-zoom out from F1 view
V-Rotates View
1 and 3 on keypad- shrinks or grows the resoluction of the screen
- and + on keypad- some type of brief zoom, unknown otherwise
/-Brings you down from floating
F6 : Look through the eyes of other people in the mission
F7- automatically kills you
F9 : Return to the player you were using to complete the mission
F10 : Switches from Debug mode to Normal mode
F12 : Level Skip
[ and ] : brighten and darken the screen
< and > : Make the player float up or down.