Press Shift + ~ to display the console window and type "helpusobi 1" or "devmapall" to enable cheat mode. Then, enter one of the following codes at the console window:
God mode: god
Unlock everything: give all
All weapons: give weapons
Full ammunition: give ammo
Full health: give health
Full armor: give armor
Full force bar: give force
Full inventory: give inventory
Full battery bar: give batteries
999 health: undying
No clipping mode: noclip
Disable enemy AI: notarget
Spawn indicated weapon: give weaponnum [weapon number]
Spawn indicated item: spawn [item name]
Level select: map [level name]