Game Engine

IW Engine
The IW Engine is the ugly, outdated game engine powering the Call of Duty series.

It is used by many games, including:
 * Call of Duty 2 (2005)
 * Call of Duty 4: Modern Warfare (2007)
 * Call of Duty: World at War (2008)
 * Call of Duty: Modern Warfare 2 (2009, IW 4.0)
 * Call of Duty: Black Ops (2010)
 * Call of Duty: Modern Warfare 3 (2011, Modern Warfare 3 engine)

Call of Duty 4 was powered by the IW 3.0 engine. World at War, created by Treyarch, was also based on a modified and improved version of the IW 3.0 engine.

Modern Warfare 2 was heavily improved on the IW 4.0 engine featuring texture streaming technology to create much higher detail in the environment.

Black Ops, in fact is not based on the Modern Warfare 2 engine but on the World at War engine, which itself was an improved version of Call of Duty 4's engine. This resulted in the texture quality of Black Ops being slightly lower than that of Modern Warfare 2.