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.
Wrong engine, SoF was idTech 3.
Nevermind, turns out SoF 2 was idTech 3, or at least so say some sources.
Soldiers of Fortune was made with id Tech 2.
Soldiers of Fortune II: Double Helix was made with id Tech 3.