Numpad 1: Super Health - turn on and you are impervious to most damage.
Numpad 2: Unlimited Ammo - the currently selected weapon will have 999 ammo. You will have to turn this off and back on if you swap weapons.
Numpad 3: No Reload - the currently selected weapon will have no need to reload. You will have to turn this off and back on if you swap weapons.
Numpad 4: Unlimited Sprint - toggle this on and you can sprint indefinitely in those areas that allow you to sprint.
Numpad 5: Unlimited SlowMo - toggle this on and you can engage the slow motion mode of the game indefinitely.
Numpad 6: Unlimited Grenades - this will give you the ability to throw the current selected grenade type indefinitely. You will have to turn this off and back on if you swap grenade types. This will also give you grenades if you do not have any, however the grenade icon will not display until you actually pick up grenades. If you press this option and don't see the icon for grenades you can still throw grenades indefinitely.
Numpad 7: Super Accuracy - press this and the currently selected weapon will have perfect accuracy. This only works ONE WAY and cannot be undone.
Numpad .: Save Position - save the current position of your character in the game world.
Numpad +: Teleport - teleport to the saved position.
Numpad -: Undo Teleport - undo teleport.
Numpad /: Hover Up - this will zoom your character up into the air. Be careful with this option!
Numpad *: Hover Down - this will force your character down through floors. Be careful with this option!