Invisible wall

Invisible Walls are a term used by many Halo 2 players who do tricks and glitches, usually involving exiting to the outside of a level even though these walls exist in all three games. In most cases it is impractical to try to get through one in an actual game when you're trying to win. The invisible walls act like any other wall, with the exception that they are of course invisible and usually encircle the map. Often times just outside of an invisible wall is a kill barrier, which is best described as a zone in which once you walk into it, you die suddenly for no apparent reason, although most of the time it says you fell to your death. At other times especially on Halo 3, when you die behind these walls it will say "Killed by the Guardians" There are ways up and or through these invisible walls, however as climbing outside of the level in a match is considered cheating, no details will be given at this time.

Getting Past Invisible Walls
A lot of people make it part of their daily life to get past these walls, with most of them using forge. A lot of these people will post a video of them doing this on youtube.

Sword Flying
The sword lunge is a very practical way of getting past invisible walls. With one player on the other side of the wall, you can lunge/cancel on him until you go through. If there is a height limit on it, such as the invisible wall on the top of Gemini, you can lunge upwards and over the wall by being farther below the "Lunge Host".

Sword lunging is not the quickest way of getting past an invisible wall, however, but it takes less know-how to accomplish. This will not work on every wall either.

Super Jumping
Super Jumping is a glitch in the game that makes it possible to get to higher areas within levels, places that are not supposed to be gotten to without a Banshee, or at all. They are useful in getting passed invisible walls that Banshees cannot get out through, or going on foot. The super jump on Ascension is a good example of getting passed an invisible barrier, although, the two person Banshee trick will work, it is easier to do the super jump during matchmaking.

Super Jumps can take time to learn, and are not always easy to accomplish on first tries. They can be tricky, making the player go through several elaborate tasks before being done. Jumping on different ledges and using perfect aim and timing.

Although it is easier to get over most invisible walls with the super jump, it is harder than the sword lunge, unless you know what you're doing.

Normal Jump
On the first 0-G part of the level Cairo Station. If you manage to get to the airlock furthest from view from when you leave the first airlock, you will notice that the In Amber Clad is not very far away. If you jump from the furthest point reachable on the airlock ceiling, it is likely you would have crossed the wall, which on the entire level is only several inches tall.

"Overload and Push"
On forge, place 2-4 tripmines and set them to instant respawn. Repeatedly throw them until the map is overloaded. Spawn a turreted vehicle (Warthog, Scorpion, etc.), or a turret. Allow the second player to enter the turret. Pick up the vehicle/turret and turn it so that the player is on the side towards the barrier. Push them through. If they do not pass through, turn them away from the barrier, push it in and drop it. Pick it back up and resume pushing. When you are outside, dismount and you should be outside of the Barrier.