Press ` in game to bring down the console, or press TAB for the quick console. Then type one of the following commands:

God - Toggle God Mode
Amphibious - Underwater Breathing
Fly - Fly Mode
Ghost - Walk through walls
Walk - Return walking to normal
Invisible [bool] - Turn inivisibility on or off (true / false)
Teleport - Teleport to where your crosshair is pointing
AllAmmo - Full ammo on all possessed weapons
Allweapons - Give all weapons
Loaded - Give all weapons and full amo on them (combo of 
allammo and allweapons
SkipMatch - Win the current match and advance on the ladder
JumpMatch [int] - Jump to a specific match on the ladder, where 
(int) is a number. For example 43 for ladder 4, 
rung 3
ChangeSize [float] - Change the player size by factor # (i.e. 0.25 or 
2.0)
LockCamera - Toggle locking the camera in its current position
FreeCamera [bool] - Delink the camera rotation from the actor
ViewSelf [bool] - Reset the camera to view the player (true to be 
quiet, false to have sound)
ViewBot - Cycle the camera through the viewable bots
ViewFlag - View the actor current carrying the flag
ViewPlayer [string] - Change the camera view to the given player
ViewActor [string] - Change the camera view to the given actor
ViewClass [string] - Change the camera view to the given class
KillViewedActor - Kill the actor the camera is currently viewing. Do 
NOT kill yourself! (Game will get stuck)
Avatar [string] - Possess a pawn of the given class
Summon [string] - Summon the given object
SetCameraDist [float] - Set the distance the camera has from its target
SetGravity [float] - Change gravitional pull
SetJumpZ [float] - Change Jump height
SetSpeed [float] - Mutiply the Player water and ground speed with the 
given value
ListDynamicActors - Output all dynamic actors to the log file
FreezeFrame [float] - Pause the game for the given duration
SetFogR [float] - Set red color component of fog
SetFogG [float] - Set green color component of fog
SetFogB [float] - Set blue color component of fog 
SetFlash [float] - Set the duration a screen flash takes to fade away
CauseEvent [string] - Trigger the given event
LogSciptedSequences - Toggle logging for all scripted sequences
KillPawns - Kill all actor pawns except the player
KillAll [string] - Kill everything of the given class, 
i.e. KillAll Pawn
KillAllPawns [string] - Kill all pawns of the given class
PlayersOnly - Toggle the level to a players only level
CheatView [string] - Toggle to view to the given actor
WriteToLog - Write the string 'NOW!' to the game log
ReviewJumpSpots [str] - Test jumping, the parameter can be 'Transloc', 'Jump', 'Combo' or 'LowGrav'.