Sierra Studios and Gearbox Software announced Thursday the development of Opposing Force, the first official add-on for the best-selling hit Half-Life.

　　Half-Life: Opposing Force, developed by Gearbox, will let the player assume the role of a soldier (not Gordon Freeman) at the Black Mesa Research Facility. Players can experiment with a variety of new human and alien weapons, a new alien race, a single-player experience on par with Half-Life, and a variety of new multiplayer maps.

　　"Gearbox is extremely psyched to be working with the superior Half-Life game system and universe," said Randy Pitchford, lead designer of Half-Life: Opposing Force at Gearbox. "Our number-one goal is to preserve the integrity of Half-Life and provide new experiences that expand upon the sensation of the original - we intend to make Half-Life fans very happy."

　　"Sierra Studios is excited to formally announce this expansion and to be the first to work with Gearbox Software," said Doug Lombardi, product manager for the Half-Life franchise. "Op For will take full advantage of the remarkable technology that Half-Life produced; including: enemy AI, rendering technologies, skeletal animation system, and the extraordinary multiplayer technology that helped Half-Life become the quintessential benchmark action game."

　　Gearbox is a new company founded in January 1999 and based in Dallas, Texas. The crew's resumes included stints at other gaming developers, including 3D Realms, MicroProse, and Ritual. Opposing Force will be the company's first game in the market when Sierra releases it this fall.