Avoid Falling Death
When you fall into a pit, repeatedly press Y to switch weapons while falling. If done correctly, you will fall, but not die.

Different Ending:
Beat Halo's Campaign on Legendary to see a slightly longer ending movie.

343 Guilty Spark Glitch
Go to the level "343 Guilty Spark." Right when the Pelican is about to drop you off, throw some grenades. It will make a glitch happen, and you will stay on the Pelican. Don't jump off. The Pelican will fly very far away, then it will land at the edge of the level. Get off the Pelican. You will be seeing some 2-D trees and some other cool things. Also, if you walk around alot, you might find a marine. He will just sit there; not reacting to anything, unless you shoot him. Also, if you go to the entrance of the building that holds "The Flood," you will see some Covenant Grunts shooting the air. If you look closely, you can see FLOATING assault rifles shooting them back. After a few seconds, they drop to the ground. You know that little movie you watch later where you find Private Jenkin's helmet? Yep, you guessed it, those guns were being held by the marines in the movie. It isn't possible to get to that area fast enough, unless you use the Pelican glitch.

Hidden Grunt
In the last level "The Maw," you need to go down the very last hallway. To your right, there should be an opening in the wall just big enough for the Warthog to fit through. It leads to a dead end, but you find a Silver Grunt there. He won't attack you. After a few screams of terror, he wil say something like "It's a good thing that the food nipple was waiting for me on the starship, because I worked up a big grunty thirst."

Easier Maw (2 player)
When entering the large engine room where you go to the 3rd floor and activate the panels and that in-turn opens the engine, where you throw a grenade or fire missle into the open engine, if the second player never enters the room only the small flood skulls0-suckers will enter -NONE of the larger Flood or the Flying laser guys will ever appear.
As soon as the final engine is destroyed and player 2 enters, the large Flood will then appear... Bypass that by only having one player finish the level off.

Glitch movie in Two Betrayals
To have the chief die in a movie sequence in Two Betrayals (ending): in
two player mode, have one player enter the last pulse generator without shooting the robots and just explode the generator while the other waits near the checkpoint hallway, after it explodes have that other player run outside so the other player inside the pulse generator with be transferred back with the other player. when movie sequence starts the robots with start shooting their lasers at the chief until he falls down, but you will still here his voice!

Kill your opponent with ease
just hit him with the B button(melee attack)in the back, it will die instantly! Also try it in the two or more player mode!

To reload faster
Hold X for a little bit, hit B and you will reaload much faster!

Level:
Keyes

Section:

Escape via the Shuttle Bay

In this level, after you are finished with Keyes and before the Flood come pouring into the room, run down the ramp from Keyes, turn left and run past the second door on the left (where the Covenant are). Just get close enough to the door to make it open and continue running to the back of the control room - stay out of sight as best you can. The door will open, the Covenant will enter the room and the Covenant and the Flood will beat the snot out of each other leaving you to mop up 1 or 2 flood (usually) at the end. SPF