While playing, press [CTRL] + [ALT] + [~] (tilde) to bring up the console, then type any of the following codes:
Code: Result:
cmd(godmode) God Mode
cmd(noclip) No Clipping
cmd(giveall) All Weapons/Items
cmd(selfsummon) Spawn Another Riddick
cmd(kill) Suicide
cmd(cyclecamera) Switch 1st/3rd Person View