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.