Isolation

Isolation is a multiplayer map featured in Halo 3 that takes place at a Flood containment facility on Installation 00. The environment is a small, isolated bio-bubble that has contained the Flood on the Ark. The Milky Way Galaxy hangs in the sky. The top level is grassy and untainted, but in the underground caves, there is an obvious Flood contamination. Its open layout, with two bases, makes it a good map for Slayer, Team Slayer, and Symmetrical Objective gametypes.

Layout
Despite its regular appearances in Free for All and Team Slayer matches, it was designed for symmetrical objective games. It features two symmetrical underground bases, a grassy hilltop above, Forerunner architecture, and the underground caves of Flood infected biomass.

Topside
Isolation has an ovular shape to it when observed from above. It is a symmetrical map that consists of two levels: above and below. The upper level is a grassy hilltop with Forerunner architecture woven into the terrain. To the north, at the crest of the hill, lies a silver-Grey multi-level Forerunner structure. A Battle Rifle spawns at either side of this tower. It can be used either for shelter (underneath, where the Shotgun spawns) or as a sniper perch (by standing on top). Directly behind this sniper perch is an escape chute that provides quick, one-way access to Isolation's lower level through a Porta. From here, the player can go to his left (east), right (west), or move forward (to the south); you cannot regain entry to the sniper perch by going back up the chute, not even on a ghost or mongoose.

Underground
Going left or right will lead to one of the cave's side entrances. At either entrance is a man cannon, which will blast you back to the top of the map. Going south will take you toward the mouth of the cave. Midway through the cave, there is a concrete bunker on either side. The bunkers have portholes for weapons fire. The bunkers can't be entered here. A little further south is where the Rocket Launcher and Ghost spawn. At the southernmost end of the cave, a thin rock ridge extends upward around the map's wall. This makes for another excellent sniper spot. Directly above the mouth of the cave is another Forerunner structure in the shape of an archway, which is rusted-brown. There is another drop-down here, which will put you near the Ghost/Rockets.

Bunkers
On the east and west sides of the map, in front of the two Man Cannons, is a Mauler, and next to that an entrance to each of the respective bases. A Regenerator exists in the main pylon of each base, as well as a Battle Rifle, Spike Grenades, and a Brute Spiker. You can either take a ramp down, or drop in from a hole above. Just above this area is the Brute Shot, a Battle Rifle, Fragmentation Grenades, and a Mongoose.

Changes For Matchmaking
Isolation has been slightly altered for Matchmaking. The only immediately noticeable change is the removal of the Flare from the Silver Structure on Topside. Flares now no longer occur in any matchmaking game.

Strategies

 * Rushing for the Ghost and the Rocket launcher at the beginning. However, also camping beside either of the two and waiting for others to ambush as they attempt to pick them up is also a good tactic if used well.
 * Isolation is a very unpredictable map. Try assuming opponents attacks and surprise them with your own bold moves.
 * If sniping is your preferred tactic, taking the Sniper Rifle and staying on the outermost edges of the map helps to prevent you from being flanked. A regenerator with an Assault Rifle is usually good backup. But make a few kills then move position, people will start hunting you.
 * Entering the lower levels through the "chute" is a good escape tactic. While being chased, strategically throwing grenades toward the exit of the chute can kill or wound any would-be pursuers.
 * In the lower levels, there are the many "spore pods" that explode, with some power, use this to your advantage.
 * Grab the Ghost and find people in the lower levels, as this is a tiny area that is hard to escape, so they are trapped while you splatter them.
 * Climbing the trees in this map can provide good ambush points. If you go to the end branches and crouch with a suitable weapon you can sometimes and with practice, occasionally, score easy kills this way because opponents that are not extremely attentive will become disorientated thus easy targets.
 * In CTF, you can pass the flag through the windows. If you have someone in the flag rooms and someone in the basement hallway, then you can end a CTF really fast in your favor.
 * Holding the structure at the top with a team is extremely effective, as you cannot be flanked, especially if your team has good aim and plenty of Battle Rifle ammo.
 * A team member can stand on top of the structure can spot enemies and call out their position so the whole team can use the high ground to kill them.
 * Also, if overrun the shotgun spawns below so keep one handy and fall back down the chute and blow all the attackers away.
 * Get the Shotgun, preferably the Battle Rifle and keep a Regenerator to stay on the open field and you can get some kills using CQB and long range shots. Use this technique and repeat it again, however go to the shotgun spawn first because it respawns very quickly.
 * The side lifts can be a handy escape from attackers. Sometimes you can land in a tree and your pursuer will be looking for you on the ground.
 * A somewhat bold and insane tactic is to drive a Mongoose with a passenger wielding the Brute Shot. This is very effective for catching enemies’ off-guard, though you are very vulnerable to Battle Rifle fire.
 * In gametypes such as Braaains, an infection game, If you start out as a human, try to communicate! Get the team to follow you down to the bunker. The best bunker to be in is the orange one. Not the blue one. The reason for this is because the zombies spawn near the blue one. Once your team is in the bunker, give each one a separate job. Have some people guard the doors, some guard the windows, and some guard the hole in the ceiling. Usually the zombies will have a tough time. But if they get one of your teamates, zombies will multiply fast and people guarding the doors will most likely be killed first.
 * Get the sniper, and go to the right base with the trees in the shade. There is a tree you can get on, so try to get up there and snipe.
 * For FFAs and Multi-Team, it is advisable to try to stay on the edges of the map to prevent yourself from being ganged-up on.

Forge

 * You can create Banshees on this map, adding an element of surprise to the game.
 * If you are flying upward to the top of a wall, you will die, but the Banshee will glide over the wall, and it will not respawn.

Trivia

 * Isolation is a map first referenced in the Halo 3 Beta code, and later appeared in a leaked photo of the list of Halo 3 maps.
 * Sentinels and Constructors can be seen flying above the map and can be shot at and destroyed, however it is difficult. This is most easily done from the eastern side of the map with the help of scoped weapons. They will not, however, drop sentinel beams when destroyed; they simply explode in a blue flash.
 * The Flood Growth Pods on the walls of the cavern do not contain Flood Infection Forms like those in the Flood Infested High Charity. When popped, they scream or moan, rather than spew Infection Forms, but they do cause damage to anyone unfortunate enough to stand next to them when they are set off.
 * If you look at the Ark in the distance you can see that the planetoid is missing from the Ark's core.
 * In an interview, IGN asked Tyson Green if "there's an interesting thing that happens when you play Isolation for a while..." in which he responded "There is, but I don't want to spoil it." Many speculated that Flood would eventually spawn in the level. It has since been revealed that small Flood Pods form in the upper areas of the map and the grass seems to become covered with Flood spores, though it does take a while for this to occur. But after a while, it goes back to normal.
 * This is now one of two maps that are Flood based in Halo 3, the other being Cold Storage.
 * Elements on this map may have been inspired by the Halo 2 map, Backwash, another Flood-themed level.
 * Getting behind the Forerunner walls using Forge will lead to a full view of "The Ark" installation. Walking too far away from the wall will kill you. You can also see through the Forerunner walls.
 * If you fly a Banshee and use the Boost, flying too high will get you killed. This does not happen when you fly at the "normal" speed.
 * The wall structures on this map are similar to those found in Valhalla.