Formerly the "QUAKE 2 Engine", with pioneering innovation in 3D environments, a few of id Tech 2's most notable features were out-of-the-box support for OpenGL hardware-accelerated graphics (in addition to the traditional software renderer), and colored lighting effects. Games created on this engine technology include QUAKE II, Hexen II, Heretic II, Sin, Soldier Of Fortune, Half-Life, Kingpin and Anachronox.
Great Engine with Great games built from them. Set the par for along time along with spawning of fantastic games. This engine has held its self against many other engines at the time of the release and even now. 7/10