Bring up the cheat console by pressing 'Tab' and enter the following codes

God Mode: God
All Weapons: AllWeapons
Max Ammo: AllAmmo
Max Ammo and All Weapons: Loaded
Infinite Oxygen: Amphibious
Teleport to Crosshairs: Teleport
Third Person View: ViewSelf

Invisible to Enemies: Invisible True
No clipping: walk
No Clipping: Ghost
Teleport to area you are looking at: teleport
Change player size: changesize

Change player speed: setspeed

Set Jump height: setjumpz

Set Gravity: setgravity

Set slow motion: slomo
Flight Mode: Fly

Summon requested class: summon

Kill Pawns and enemies: killpawns
Get a Pawn of indicated class: avatar
Camera and Pawn not rotated together: freecamera