Treyarch NGL is a proprietary 3D Game Engine developed by Treyarch. The engine has been retired by Treyarch who are currently using a continually modified version of the third iteration of the IW Engine.
The game is generally associated with first-person shooters due to its use in the Call of Duty video game series, however, it has been used by Treyarch in other games of various genres, the major of these games coming out in 2002. The first game made using the engine was NHL 2K3 and the last was Call of Duty 3 before the engine was promptly retired by Treyarch in favor of IW 3.0. It is rumored that some of the engine's properties have been put into the modified IW 3.0.