Longest
From Halopedia, the Halo wiki
Longest is a multiplayer level in Halo 1. It consists of two long hallways with a base at either end. It's great for Grenade Sniping. It has been revamped for Halo 2 and is called Elongation. There have been observations that the style of room is used in the level 343 Guilty Spark, and that it commonly bears the same weapons and strategical placing.
The map has several ramps(and on top of one of them an active camouflage is found). A good strategy is to keep your distance when it's crowded and pull out an assault rifle. Fire small one second bursts to make headshots easier.
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