Half-Life: Blue Shift
As with Gearbox's previous expansion pack, Opposing Force, Blue Shift returns to the events of Half-Life, but portrays the story through the perspective of someone else. You play as security guard Barney Calhoun, hired by the Black Mesa Research Facility, who must fight his way to safety during an incident. Blue Shift also includes a pack that upgrades the Half-Life models and textures.