All Weapons Multiplayer mode:
Go up to an Elite with a sword, and kill him by hit him with a machine gun. Once you have killed him go on until you get to the next checkpoint. Once have got a checkpoint turn your Xbox off and then on again. When you go back on to that level again you will have all the weapons there are.

How to turn invisible with a shild.:
Fined two items one is blue that is the one to make you invisible and the other is red that gives you a shild.

Unlock Levels:
The cheats these other fools have submitted are obviously garbage and made up. You can unlock the foundation MP map by finishing campaign mode on easy. there are also two other maps to unlock: Marathon and Conclusion. Try finishing harder campaign modes to unlock these levels.

King Osman Gun:
As soon as u start a multiplayer game, pause the game immediantly and press L,R,L,R ,up,down,L,A. this will cause you to start with a King Osman Gun next time you die.

Master Chief turns into Samus:
Go to Metropolis under heroic mode and as soon as you appear dont move. Look directly up, then directly down, then look striaght. Click the left trigger and hold it down and press Y,Y,B,White, Y,B,A,A,A, White, X,Y,Y, A, Black. After that done, leave game, go settings, create a profile with the name being “Samus”. Restart your Xbox and in campaign, under heroic, Master Chief should now be Samus.

Blue Screen of Death in Zanzibar:
In the multiplayer map Zanzibar, there should be a computer on the upper level on the defense side that opens up the main gate into the base. After you activate this, the screen goes blue with the infamous BSOD.

Assassins Mode:
A skull similar to the one that activates blind mode can be found if you Start on “regret”. After the first lift ride (before the first underwater elevator), grenade jump from the front awning of the lift to the ledge in front of you (the one with two turrets).Grenade jump AGAIN onto the next ledge.
Make your way to the back of the building. On Easy, you’ll only find the skull. On Legendary, however, 2 invisible Elites carrying swords just shake their heads wildly, ignoring you completely.

Angry Mode:
When you are the Master Chief trying to recover the index from the Prophet of Truth on the Covenant Holy City go until you reach the first outdoor area with dirt and vegetation. Take a right as you enter this room and run up to the wall past the gravity lift that leads up to the sniper point. Get on top of the wall by going up the dirt mound on your left. Follow the wall until you reach the floating skull called “Angry”.

Glitch on Delta halo mision:
Right get up to the bit where you get a scorpian tank, then get to the bit where a pelican drops ammo and marines and there should be some sheilds, destroy them with the tank machine gun, then go and drive then park over them,STAY IN THE TANK! And wait, on halo:combat evolved the sheilds broke when parked over but in halo 2 the spring you up! the tank(along with you in it) are sent hurtling up and can land in an unlimited amount of places! some times you can land on the pelican its self and fly off or you could go so high that you get stuck in the air!(dont worry though as the checkpoint is just b4 where you go over the sheilds) and where you go all depends on the order of destroying the shields and where you put the tank. Be warned though this can cause you and the tank to go straight into a wall causing the tank to explode and sudden death!

Black Eye Mode:
In the level “The Great Journey”
It is on top of the contol room where Johnson blows up the door. Shield won’t regenarate if picked up.

Cheat codes for Quake 4 for Xbox 360 Console

Get all:
Press Back during game play, then press Up(2), Down(2), Left, Right, Left, Right, B, A.

Health:
Press Back during game play, then press B, A, B, A, Up(2), Down, X.

Ammunition:
Press Back during game play, then press B, A, X, Y, Left, Right, Left.

Invincible:
Press Back during game play, then press Down, Up, Down(2), Up, Right, Left, Right, Y, X(2), A.

Secret passage in Mission 7
Before Mission 7, select the demolition kit from the weapons menu. During the mission, after you kill the two brothers go across the bridge towards the rocket. When you get to the rocket, go left and down that road. When you get to the end of the road, there should be two doors (one on the left and another on the right). If you try to open them, they will say “secured”. If you go on to a ramp that is on the right side of the left door, there will be a crack in the wall. Use the demolition kit to blow up the crack to get into the door.

Easy points
To get easy points, get an outside scorer and press LT + X. He will put the ball behind his back and lay it up. It cannot be stopped even by an inside stopper and will always work.

Bonuses
Break the indicated high score in an action level to unlock the corresponding bonus:

Big Troll heads: Thorn’s Castle, 2,500,000 points
Big Kameo head: Thorn’s Castle, 2,500,000 points
Boss battles: Water Temple, 2,500,000 points
Kameo in her original purple costume: Thorn’s Castle, 100,000 points
FMV player: Forgotten Forest. 1,600,000 points

Faster riding on horse
Hold (Dash) while repeatedly jumping your horse to travel about double the speed.