In Half-Life: Opposing Force, which was named PC Action Game of the Year in 2000 by the Academy of Interactive Arts and Sciences, you play as Corporal Adrian Shephard, a military specialist assigned to eliminate Freeman. Half-Life: Blue Shift puts you in the role of Barney Calhoun, a security guard and ally of Gordon Freeman (from the original game) who infiltrates the Black Mesa Research Facility to explore previously unavailable areas while dealing with an entirely new storyline. The 3D-accelerated High Definition pack upgrades weapons and characters in the original Half-Life as well as the new episodes. Gearbox Software follows their commercially successful Half-Life: Opposing Force with a 'complete expansion set' that includes not only the Opposing Force game and the Half-Life HD pack, but an additional two episodes.
