Multiplayer Map- Foundation via Xbox Live
Bungie has decided to give the multiplayer map to anyone who signs on via Xbox Live. You will be prompted with an update as soon as you try to sign on. The update will unlock the map, improve support for 480p resolution display's, and speed up wait times in matchmaking.

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".

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.

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.

Blind Mode
At the beginning of Outskirts jump on top of the light on top of the door with a crouch jump, then jump to the left platform. Turn to your left and go down the long dark corridor and pick up the skull; it will say blind and your screen will flash black for a while. In this mode you can not see your weapon, body, shields, ammo, or radar. To get rid of this feature use the following method: 1. Turn off your XBOX or Save and Quit. 2. Go to Campaign and select level and choose Cairo Station. 3. Skip the cinematics and then Save and Quit. 4. Go Outskirt and your hud is back.

Catch Mode
Right after u get out of the sewers (Tunnel), there is a big area and 2 ghosts, kill every thing first, then go to the middle of it where u see a arc that leads up onto a building, throw a grenade down and jump by it to get enough height to start climbing it. When you get to the top take a left and hug the wall around the structure and the skull will be there. It says Catch

Envy Mode
On the level "Delta Halo" on Legendary Difficulty, Progress until you reach the area during the "Push through the covenant held ruins" where you have to clear a Landing Zone for the Pelican to drop weapons. You will know you are in the right area when cortana says "they're pouring out of the center building". Anyway that area has Plasma turrets along its borders. A little bit after the left side turret you will see the outline of a door in a wall, but the door has a solid rock slab in it and a rock in front of it. Jump on the rock then jump to the ledge above the door then jump on the ledge to the left. Now jump onto the building with the sealed door using grenades. Atop the building you will find two dancing elites and the "Envy Skull". Pick up the envy skull and you will be able to use Active Camoflage like the Arbiter.

Famine Skull
After you get off of the slowly decending elevator in "The Oracle", you will come to a hallway where you see a handful of dead bodies. Continue into the next room, and you will be on the second floor of a room that has windows. When you enter this room, look to the right, and find the third pane of glass. It should be to the right of a wall that has some flood guts splattered on it. Shoot out this window, and either window directly across the room. If you look below you will see a platform that has four tall posts. On the far side of the room there is a column that is right in between the two windows, on the far side of the room. Turn on your active camo, and jump to the center platform. Jump on either of the posts on the far side of the platform and jump to the column between the windows. Make another jump through the window you shot out and make a left. Walk all the way to the end and you'll find four flood elites convulsing on the floor, with the Famine skull in the middle of them. When you have this skull all weapons will have less ammo.

Ghost Mode
After the outdoor area with all the ghosts and grunts, there is an 'L' shaped room that is seen throughout the level. It is right after the armory room that is full of covenant and human weapons. Grenade jump using a jacked ghost up to the rafters and it's up there.

Grunts Birthday Party Mode
In the level Arbiter on Legendary. Once you get to the first banshee section, fly immediately straight down all the way to the bottom of the map. In one of the cracks where the large cylinders connect to the station. There will be a circle of grunts dancing around a skull. When you pick up the skull; it will say Grunt Birthday Party on the screen. Now when you kill a enemy with a projectile weapon, they will blow up like a plasma grenade was stuck to them. To get rid of this feature use the same method as the blind mode.

Hidden art gallery in the Limited Edition DVD
In the main menu of the bonus DVD, hold left for 10 seconds.Then you will be able to see the hidden art gallery.

Iron Mode
On the last Master Chief Level, on Legendary Difficulty, when you enter the final Gravity Lift, look up. A skull will pass through you extemely quickly so you must start holding X a bit before you actually pass it to grab hold of it. Once you grab the Iron Skull, Iron Mode will be activated.

Mythic Mode
In "Sacred Icon" there is a semi outdoor area which has the same type of area right next to it. There is a large sentinal in front of each one. Go past this area and down the piston and you'll be in a vary dark and dank flood infested area. There's a stack of 6 or 7 boxes as you enter the room. Use them to jump up to the landing above. There are a handful of alcoves on your right hand side. The skull is in the third alcove, floating above a dead human flood. When you are in this mode flood are invincible when driving vehicles.

Posters at the Old Mambassa Crash landing *after Cairo*
After you crash land on Old Mambassa, you can see posters all around with the Master Chief from the demo and some grunt posters.

Sputnik Mode
At the start of "Quarantine Zone" turn directly around, and you should see a tunnel. Head down the tunnel and go straight until you exit it. Go straight across the open area, and you'll come across a broken pipe tunnel on your right. Straight in front of you is a small ledge running across the wall, above the green pit. Carefully get onto that small ledge and walk all the way to the end of the ledge to find the Sputnik skull. In this mode explosion force and melee force is greater.

Unknown Skull
At the begining "Armory" wait in the room until the Sarge starts telling you to get into the elevator. You MUST wait for him to say "Would it help if I said please?" When he says this, get into the elevator and go down to the tram. Get on the tram and face towards the INSIDE of the building. Press up against the glass doors towards the inside of the building. You should hold 'X' down, and you should pick up the skull. It's on a stack of green crates, near the end of the tram ride.

Infinte Camo
After getting the envy skull go through a checkpoint while in active cammo mode. To be safe use "reset to last checkpoint" so you can check if you did it right. Save and quit; then turn off the xbox to remove the envy mode. When you reload your file you will find yourself with unlimited camo.

Skip tough Brute battle before the end boss
When you are flying around in the Banshee during the final level when you are giving support to your ally. You can skip directly to the final boss sequence if you are still in the Banshee after te door gets blown open. Fly to the right of the control centre building and aim towards the bottom right and if you fly close enough you should get a white screen indicating that you have started the cutscene. When it's over you will be at the final boss without fighting your way to him.

Unlimited Sword
Beat the level Delta Halo on any difficulty with an empty sword. After the cutscene finishes switching levels, you'll have a zero energy sword, but it acts like a normal sword. You can't see the blade though.

Changing Split Screen Type
The multiplayer split screen type is determined by the video settings on the Xbox dashboard. For Horizontal split screen, the Xbox must be in fullscreen mode. For Vertical split screen, the Xbox must be in widescreen mode.

Get a Scarab Gun
This is done on the level Metropolis and is easiest when done on Co-op. When you start out, cross the bridge. Take out every enemy and even your marines. When you're near the end, Cortana will say something about a "Welcome Party". Three Banshees and a few ghosts will appear. Take them all out. Then 2 Wraiths and 2 Banshees will appear. Take out both Wraiths, and only one Banshee. Have Player 1 continue through the tunnel, but have Player 2 stay outside and distract the Banshee. Once Player 1 reaches the area with the circular opening (a Jackal with a Beam rifle is present), take out the Jackal and head back to where Player 2 is. Here is the hard part. Get the Banshee to follow both players into the tunnel. Do not board it yet! The first few times it will come at you and fly back out, but stay where you are. It should come back after you. (If it doesn't, go back outside and try again). Eventually, you'll have to get it over two road blocks. Once it is past the second one, have both players stand near the entrance of the room where Player 1 took out the Jackal. It should fly at you and get stuck. Shoot off both of its wings so it can fit thru. Have Player 1 walk slowly in front of the Banshee, making it follow him. Player 2 should be behind it, gently pushing it. Take it to the left and get ready to board it. As soon as you hit the checkpoint, the Elite in the Banshee will disappear. You only have about a second to get in before the Banshee also disappears. Both players should press X quickly. If done right, one of the players will be driving the Banshee! Take it outside and directly up. Very high in the sky are two skyscrapers with two bridges connecting them. In the middle of the bridge closest to you, there is something that looks like a plasma rifle. It's actually a Scarab gun! It has infinite ammo, so have fun. Just don't aim at the ground...

Skip Sniper Alley
Level: Outskirts
How To: Once you have killed The first hunter pair at the start of the level walk through the hole in the wall they created. walk through and look around. there should a destroyed wall to the left of you. jump on to it and make your way upward by carrying on jumping upwards, crouch jumping when nessasery. you should eventually reach the roof tops (it may take a while to find and/or reach). from here head toward the left hand side part of the roof tops. you should see part of the destroyed highway that the first pelican flys along once it has picked up the sgt. jump onto this highway and walk across it. at the other side you should see a slope and in the distance the hotel where the next group of marines are pinned down. jump off the hight way and walk up this slope to reach the hotel skipping the sniper alley.

Two hidden swords on Halo Delta and a fight to skip.
On Halo Delta, get to the structure where you can't go any farther with the tank. As you enter into the area, go left up the ramp and then up the little ramp until you come to the large block butted up against the wall. This is where you jump up to get to the Envy Skull (consult for more detail). There is a secret entrance behind this large cube. I found the easiest way to move it was with the tank, although grenades do the trick just as well. You can drive the tank up there with a little patience. Aim at the WALL to the left of the stone, The explosion with slowly move the stone out of the way. Once the path is clear, walk up the dark ramp and there will be two dead grunts and two swords. There is also a high ledge in the next room that you can grenade jump up to, and then frag grenade jump up one more level -- allowing you to skip the fight inside the structure.