Halo

On the level: Assault On The Control Room, take any vehicle and move through the level until you get to the part where at the bottom of the screen it says: "Rolling Thunder". Instead of going forward and look back at the Marines (if you helped them survive through the level until this part) that were chasing after you on foot. They will be frozen in running position. This happens because you took a vehicle through the checkpoint. I recommend not killing them, because if you go through the level normally and come back, they will be unfrozen.

This isn't really a cheat just something to fool around with because i have gone through the game looking for fun errors (and found lots). On the last level (the maw, chapter: .....and the horse you road in on) i was messing about and found this, when you start the level your inside one of the escape pod bays (a small tunnel like thing), walk out of this one and to your left there should be another, walk in here and walk directly down the middle, look down and you should see a really big fall onto a cliff, walk as close to the middle of the tunnel as you can and then walk of the edge, you should fall bounce off a small hill and land still alive (try again if you died), you will now be stuck on this cliff and you can have a look at the ships outside and see how much detail the makers have really put into the game......have fun!!!!

Here's a good way of killing elites or hunters in legendary. get a needler and some ammo and just unload it on an elite and watch the show --NOTE-- You have to get in close enough for the needles to find their mark, and the delay until they explode leaves you wide open for their plasma rifle, so bring a backup weapon.

For the hunters, unload an entire clip at their backs so the shot doesn't reflect off their shield and start shooting at them with another weapon while waiting for the needles to explode (or just sneak up on one and smack him in the back, and if you cant to that...a well placed plasma grenade to the head should weaken it, but it will most likely just piss it off.)

When you see large groups of grunts and jackalls you usually don't need to use grenades because they're so damn weak but in legendary every cheat helps. Throw a plasma grenade and stick it to one of the low ranking grunts(yellow or red bio suits not so much on the silver ones) The grunt screams and runs to the big group of guys screaming "GET IT OFF! GET IT OFF!" then he blows up and kills the rest with him.

This is not much of a cheat rather then something I discovered. You have to do this in co-op mode. First go to any level if one of you dies (this has to be done in a building) back up into a corner and sometimes that person will be reborn on your thus making that person able to jump higher.

Assault on the control room: How to get a Banshee sooner than the bridge, 1 player.

Fight your way through the level to the first snowy open area, kill the enemy tank and all the rest of your enemies then hop into the Warthog. Make sure you get the Rocket Launcher and the Sniper Rifle. The next open area has a battle raging and an empty Scorpion, hop into the Scorpion and waste all the Covenant with the cannon. To the left is tunnel, to the right is the obvious way to the next open area, go to the right and clear the enemies around the corner. Stop (If you kill all the enemies in the next open area an Elite will get the Banshee before you do and use it to attack you. You'll know you're in the right place if there's another enemy tank in the area.) Now, jump out of the Scorpion and stay to the Left edge of the valley. Look up, you should see a Ledge above you with some lights on the underside. The Banshee is on that ledge so get underneath it and shoot some rockets up to knock it off. Remember to move something forward with concussion weapons you have to shoot behind it, so use you brain. If done correctly off will tumble the Banshee, if done incorrectly it will be pushed farther in. As an added bonus the last few sections of the level will have no enemies due to the fact you've skipped so much.

In the very last level of the game, as you're driving the Warthog out of the Pillar of Autumn, get out at the 2 tunnel off of the main one and there will be a grunt at the end of it. he should say something like " I can't wait to get back to the ship and eat some grub!"

Hunters are actually pretty easy to kill, the trick is to be in close combat. Just jump to the side when they try to hit you and shoot them in the back. They have no armor on their back so 5-10 shots with the pistol takes them out pretty easy.

To get infinite grenades, scorpion, and ghost in multiplayer- Go to the multiplayer screen: go to edit game types: In that menu you will have the option to make up your own game type.

Whenever you fight the flood keep shooting them. sometimes if you don't shoot enough they will get back up and still fight you. It is best to use a shotgun it is usally a one shot one kill weapon.