Gephyrophobia is a multiplayer level exclusive to Halo PC and Halo Mac. The level is very similar to the Halo: Combat Evolved campaign level Assault on the Control Room. It consists of a large two-level metal bridge expanding over a misty pit. It was reimagined as Narrows for Halo 3.
There are three levels in total on this map: the bottom floor of the bridge, the upper floor of the bridge and the two ledges on the side of the canyon overlooking the bridge. On the lower level of the bridge, there is a Ghost and a Flamethrower at the exit of each base. The middle section of the bridge opens up to reveal a tower, which has an Overshield on the second ledge and a Health kit on the top. This tower can only be reached by Banshee (There are four on the map). This area is also a popular area for sniping. However, you will have to be on the lookout for other snipers and other Banshees. At the base of this bridge, is a stash of weapons and two Health kits. On the upper level of the bridge, there is a Health kit, two Plasma Grenades and two Ghosts near the exit of the base. Towards the middle, the bridge splits into two sides (which forms a ring around the large tower). On either side of the bridge, there are two Shade turrets, a Sniper Rifle and a Powerup. (The powerup is either an Active camouflage or an Overshield and it depends on which side of the bridge you have taken). It is ill-advised to enter a Shade because they make extraordinarily attractive kills for all players. However, enter it if you wish to take down an incoming Banshee or Warthog. On the two ledges overlooking the foggy chasm, there are two entrances to teleporters leading to and coming from each base. At the exit of each teleporter, there is a Banshee and a Sniper. If sniping, it is advised to do so from here, but take note that there is another sniper at the exit of your enemy's teleporter (as well as a Banshee) which could take you out. Towards the middle of the ledge, there is a Fuel Rod Gun.
In the bases there is an Overshield, Pistol, Shotgun, Assault rifle and a Plasma Rifle. Banshees are very popular, and can usually give you the upper hand on this map. Warthogs are located in front of the base on the top side. Capture the Flag is the best gametype for this map. Race is popular too, due to the large number of vehicles. Individual games like Classic Slayer or Oddball are not popular, because it is difficult to find an enemy.
- Gephyrophobia means "fear of bridges."
- Gephyrophobia is far larger in size than its successor, Narrows, although it shares many similarities.
- The energy beams that reside in and out of the bridge, though seemingly just light, are solid and can be climbed. When shot these beams emit purple electricity.
- It is possible to land a Banshee on the top of the center support tower, which is an excellent sniping location, and has a health kit situated in the center. However, should someone knock off the Banshee while you are on the tower, you will be trapped, unless the shield setting is on 400% then you could climb down the beams connected to the tower and jump to the lower slope connecting the lower bridge to the upper level. Note that it is important to crouch before hitting the slope itself or you will not survive the fall.
- There is a secret room at the bottom of the map containing both Health Kits and Weapons. To get to it one must enter a Vehicle with an Overshield and drive it off the bridge. With enough luck, the Vehicle will absorb most of the damage during your fall. Note that you must keep your vehicle stable during your descent or you will run the risk of falling out, after which it is unlikely you will survive the fall.