Halo

In the levels where you must face the Covenant there are certain aliens called Elites. They are the big ones which are usually blue, red, or sometimes yellow. If you have a gun with a scope ie; pistol or sniper rifle,try to get behind an elite without being seen by it. Next, Zoom in at the back of it, you will see yellow spots on his back or his head. If you shoot them a yellow liquid sprays out and they die instantly. This cheat helps because you only need to use 1 bullet and you do not have to get in close to kill it. It also looks cool when the yellow stuff sprays out.

To reload most weapons faster, press X and shortly after that press B to Melee. Note: For the shot gun this will cause you to stop reloading all together.

When yopu get to the first bridge on the assault on the control room, turnt to your left and Jump off (should only be done in 2 player cooperative). there will be a ledge. follow the ledge down until the end ofit. Kill one of the players. when the dead players screen goes "waiting to respawn" you then jump down onto the next ledge and try and slide off it. if you fail try again and again. so that the dead player respawns onto the next ledge than try and attemp to slide off the rock. than if succeeded go to the landing pelican. go upto it andf than press x. it will than take you to the scorpion tank. Use that of the warthog to go to the next door. when there get the banshee. and fly around and do what ever you want.

Through one plasma grenade in a wide open spot, then stick another directly on top of it if you do this fast enough the first gernade will launch the second and vuaola fireworks.

This code can only be done on 2 players. At the beginning of the level: 343 Guilty Spark, have both players stay inside the Pelican by rapidly pressing the grenade button until both players throw the grenade. The Pelican will soon fly off with both players riding in it. Once the Pelican gets to the area with the 2 dimensional trees, have one of the players jump out. While the player that jumped out is falling, on his screen it will say: "press X to flip Pelican". Have the player that jumped out rapidly press the X button. If done correctly, the Pelican will miss the spot where it normally would land. Have the player that stayed in the Pelican get out as soon as it lands. Look on the player's screen that just got out of the Pelican. On his screen it will say: "press X to flip Pelican". Press the X button and the Pelican will flip over on it's top. Press the X button again and it will flip again and land normally. From here, you cannot flip over the Pelican anymore, however, you can melee it with your weapon and it will slide, just like any of the vehicles that you can drive. This glitch cannot be done on 1 player because if you jump out, the Pelican will disapear, and if you stay in, the Pelican will land safely and you will not be able to flip it over.

The Warthog and the Sniper Rifle is required to do this cheat. Move through the level: Assault On The Control Room until you get through the tunnel that slants up right after the part where it says "Rolling Thunder" at the bottom of the screen. Just ignore the Covenant Dropship that comes down and drops off some Covenant and two Ghosts. Quickly, get out of the Warthog and run to the top of the small hill that has a Gun Turret on it. Zoom in your Sniper Rifle twice and look to the left of the empty Wraith Tank sitting on the ice. You will see an Elite running for it. Quickly, kill him and then take out the rest of the Covenant so they do not destroy the Wraith on accident. Once all enemies are annihilated, get back in the Warthog and keep ramming one of the back corners on the Wraith. If done correctly, the Wraith will flip over. Then get out of the Warthog and walk up to the Wraith. On the screen it will say: "press X to flip Wraith". You can flip it over, however, you still cannot drive it. Explosives will not work to flip over the Wraith, as they would just destroy it.

For multiplayer coop mode, formations can be very helpful. In formation A, player one stays a little while back with a pistol or sniper and protects player two, while player two moves in with another weapon of choice (preferably human or covenant rifle). Then, player two pulls out a pistol or sniper and hides behind something while protecting player one, who then pulls out his/her weapon of choice and moves toward the enemy lines a little (of course, whoever has out their weapon of choice is also shooting the enemy). Cotinue this process for as long as need be for the time. This process can also be used for more then two players.

When there are not many enemies near, both players charge in and attack. NOTE: This can also be used as an S.O.S formation combined with other tactics (preferrably Formation D).

When there are too many enemies to take on at once, or when stealth is the key, both players stay back and snipe with a pistol or sniper rifle. This works best when there are places to hide behind such as in "Truth and Reconciliation."

In Halo, I was trying to do another cheat and it didnt work but i found something else: On the last level (the Maw), you start out in a life pod launching area. It is tunnel like and small. Walk out of it and turn to your left into the other life pod launch area. After, go back into the area where you start out in and look out of the edge. You will see the monitor's machines that shoot orange lasers at you come up (and their wings are closed ) and they will come into the launch pad where you are but they wont shoot. You can either watch them fly by you or blow them up because they are defenseless. Note: They will turn around and shoot you when they get to the end of the tunnel.