Soldier of Fortune II: Double Helix is a first-person shooter video game developed by Raven Software, a sequel to Soldier of Fortune. It was developed using the id Tech 3 engine. Once again, Raven hired John Mullins to act as a consultant on the game. Based on comments and criticisms of the original game, Raven Software developed Soldier of Fortune II to be a more realistic game, with tactical shooters like Operation Flashpoint: Cold War Crisis and Tom Clancy's Rainbow Six as inspirations rather than Quake. A sequel titled Soldier of Fortune: Payback, made by Cauldron HQ was released for Microsoft Windows, PlayStation 3 and Xbox 360 in 2007.