Halo

About halfway through the Maw, you need to traverse through maintenance corridors, you will emerge into a battle between the Covenant, Flood, and the Monitor’s drones. When you see the door out, go right to find a blood-stained health pack, go left and you will come to another door leading into a section closed off by blast-doors with ammo and a bunch of fiery rubble.

Once inside the room, you can shoot through the would-be bullet proof windows in the blast-door with any human weapon except the rocket. This is a great way to get rid of the Covenant and drones because the AI isn’t supposed to realize that they can shoot back. The flood never stop coming at this part, so don’t waste your ammo.

Beat The Maw on legendary difficulty to see a new ending movie. The new movie will feature the Sarge and an Elite fighting over an Assault Rifle. Then, both of them will look towards the Pillar Of Autumn as it starts to blow up. The Sarge will then say to the Elite: "this is it baby, hold me". Then they will hug and the game will get back to it's original ending movie with the Chief flying off in the Longsword.

Successfully complete the last level of the game in campaign mode under the legendary difficulty setting. The new ending features a human and alien fighting hand to hand. The human will say "Its over", and then they hug because they know the explosion will kill them both.

Okay, this one isn't really code, but I've done it tons of times and its pretty funny. Wherever you have flood to fight, take out an assault rifle and shoot only at the arms of the corpses, this blows them off without killing the corps completely. After that the thing keeps running at you, but stopping two feet away because it can't do anything. As long as you don't kill it, it'll be your shadow.

At the Halo start up screen, choose multiplayer mode. Choose cooperative play at the next screen, then choose your profiles at the next. Choose the level where in the beginning it says, "I would have been your daddy" (Assault On The Control Room). On the difficulty screen, choose legendary. When the level starts after the introduction sequence, have one of the players quickly press X when the "Press X to get on the Pelican" message appears. That player will re-board the ship and start flying with it down the hole. The other player will quickly die because of the aliens, and will be respawned on the spinning ring. Make sure to jump where there are gaps. If you are good enough, you can even jump to a nearby ledge. Additionally, once you are respawned on the ring, quickly jump off and fall to your death. Sometimes you will be respawned on the lowest ledge in all the blue haze, and a "Press X to flip the Pelican" will appear that the top of the screen very briefly.

In the very begging I sugest you use 3 main snipe points. 1st is at the top of the hill near the pelicans landing spot. You'll see two rocks jutting up and one inbetween them. You can duck behin it then waste everyone insight. Next is a rock closer to the edge of the hill if you go forward. Then finally go behind the large wall like thing and come out to waste the rest of them.

Alright start 343 guilty spark on co-op(note- it doesnt work on 1 player) so while your still in the pelican keep pressing the grenade button untill you run out and.. WALA! ur still in it and it will take off with you in it! anyway, it will land near the edge of the map, now get out (note- make sure that a player stays with the crashed pelican so u can spawn with him) and go the way that the pelican is facing and then jump on the entry to the building u would usually go thru on the mission then drop down and quickly look inside the entrance and u will just see 3 floating assault rifles just shooting but there is no marines holding them. now here is another glitch spawn with the other player and continue going around the edge of the map untill u find a lone marine, just standing there not moving and he has no gun (note- if u hit once he will die). and if u wait a long
time at the pelican and then go out looking again u will find some flood bodies which is weird coz u dont meet the flood yet but we have.

This isn't a cheat but it can be annoying. If you have a sniper rifle and you use the shot on a Flood the shot will go right through it which is just plain weird.

You must do this on co-op. When you get in a Banche fly around and kill your partner. When he/she is dead. Fly into a wall or tree if done right your partner will fall to his/her death. it is pertty mean but fun.

When Covenant dropship is getting ready to unload a group of Covenants, throw a grenade into the door as it opens. The blast will kill several of the enemies since they are all in one area.