The Gully is a steep canyon with (as it's name implies) terrain similar to that of Skag Gully. It mainly consists of a single large, winding path forming three levels as it descends to the bottom of the arena, with an additional area off to one side near the spawn point. At each end of the main path are teleporters made of Eridian stone blocks which allow instantaneous travel between them. A large raised platform in the centre of the canyon offers good views of virtually the entire map. As with all of the Underdome arenas, there is a large, curtained stage that dominates the lower side of the map and acts as a spawn point for any boss characters.
- Owing to the layout of the map, a Hunter with a powerful sniper rifle can do large amounts of damage if positioned in a high vantage point (a high-zoom scope may be required), although they must be wary of enemies spawning nearby and of becoming swarmed during Horde Rounds.
- The teleporters not only make travelling from one end of the canyon to the other much faster - they also offer an escape route should the player(s) get into difficulty. Enemies cannot use the devices, and so quickly teleporting to the opposite end of the map can offer time to recharge shields and reload weapons.
- As with all the Underdome arenas, the challenges (specifically the larger challenge) can be completed much faster by playing in splitscreen with a low-level character as the host and a high-level character as player two; all enemies will level to the host character, making them easy targets for the second player.