Press C during game play, then type marvin to activate the console. Press C again to exit, then press [F2] to display the console window.

Effect - Code

Edit player abilities sub-menu - edit abilities
Enable God mode - cheat god
Extend view to near infinity - zfogzone
Heal player - cheat full
Invisible to all enemies - invisible
Slightly better appearance - zhighqualityrender
Spawn indicated item - insert [name]
Switch to first person view - first person
Warp to front of Xardas' tower - goto waypoint Xardas
Warps to the Khorinis lighthouse goto waypoint lighthouse