If you throw the energy sword just right and it kills the enemy, it will turn into an axe and become stuck in the enemy's forehead.
Cheat mode
Enter one of the following codes to activate the corresponding cheat function.
Effect
Code
Unlimited bullet time
IamTheOne
Double the reach length
gorilla
God mode
iddqd
Laser guide
redlight
Super strength
bruce
Low gravity jump
nasa
Defeating Jesus
Enable the willis and newyorkminute codes. Reach the level where Jesus flies in overhead. Make sure you have a jetpack. Press Q to activate bullet time then fly around and kill everyone else until only Jesus is remains. Then, use a machine gun to defeat him.
Defeating zombies
On Zombie Challenge kill the Jesus to halve the zombies' life. They are harder to kill when green.
Exploding bullets
Go to experiment and press 7 to get the sniper rifle. Point it at the ground, then fire. You should hear an explosion. Do this near a dummy and they will explode.
Instant plasma grenade explosion
Take a plasma grenade and pull the pin. Press E to set it as your secondary weapon. It should go off. As soon as you want to use it, pull it out. It should not go off however long you hold it. Throw it, and it should go off as soon as it comes in contact with the enemy.
Sonic blast
Go to experiment and get the plasma pistol. Aim and hold the Left Mouse Button for approximately six seconds. Release it and a single shot will kill almost anything.
Axe in enemy's forehead...