While playing, press [CTRL] + [ALT] + [~] to bring up the console, then type any of the following codes:

Effect - Code

All Weapons/Items - cmd giveall
God Mode - cmd godmode
No Clipping - cmd noclip
Unlock All Director's Cut Special Features - unlockall
Spawn Another Riddick - cmd selfsummon
Suicide - cmd kill
Switch 1st/3rd Person View - cmd cyclecamera
Load Map (#=Name) - map #

Note: On the MAP command, use the names from the Install Directory\Content\Worlds.