To activate the cheats press ' to bring down the console in game and type the cheat you want to use:
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
SILENTBUTDEADLY : Makes players "FART".
FASTACTIONRESPONSETEAM : Unknown
TURNPUNCHKICK : Changes Players from 3D to 2D
1-900 : Heavy Breathing
EXPLORE : Victory Conditions On/Off
DEBUGKEYS : Debug Keys Enabled
A - Artificial Intelligence On/Off
M - Freezes you, most likely AI turned off for just YOU not teamates.
1 and 3 on keypad - shrinks or grows the resoluction of the screen.
- and + on keypad - some type of brief zoom, unknown otherwise
F6 : Look through the eyes of other people in the mission.
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.
o -zoom in from F1 view
p -zoom out from F1 view
V -Rotates View
B - Brings back to normal view / -Brings you down from floating
F7 - Automatically kills you, no matter if on team god mode or avatar god is on.