Bring up chat menu and type csmilton...then type the following codes to get what you need.
csyhwh...god mode
csguns...all guns(duh)
csammo...all ammo(duh)
csrosary...all angel spells
csessence...endless essence
csrosary - All Angelic Powers
cshealth - Full Health
csshroud - Full Armor
csessence - Full Essence
csitems - All Items
csguns - All Guns
csammo - Ammunition
cshost - No Gravity (Flight Mode)
cswire - Wireframe Level Map
cshalt - Stops Time
csportal - All Doorways Highlighted Yellow
csvanish - Kills All Enemies
csback - Quick Reset From Last Save