When you are facing a partner in multi-player and you cannot find ammunition, sneak up behind him and hit him in the back for an instant kill.

In split screen multi-player mode, equip you pistol. When you see your opposition, place the aiming circle on their chest. After each shot, aim higher until you are aiming at their head. If done correctly, it only requires three shots to kill and will leave your friends wondering what hit them.

This is a very interesting way to kill a player in a car. This trick requires is a plasma grenade and a human pistol. If your opponent tries to run you over, dodge him by moving to the left of the car. Try to get into the side seat of the car. Once this is done, throw a plasma grenade down. Jump out of the car and run. The pistol is used for backup. This may take a few times, and a few deaths.