When a top-secret laboratory on LV1201 ceases all communications, Colonial Marines are dispatched to investigate. The Marines will need nerves of steel to search for the remaining survivors. The lab corridors, air shafts, and the planet surface are teeming with lethal creatures out for blood.

The arsenal of a Colonial Marine includes a pulse-rifle, flamethrower, rocket launcher, grenade launcher, shotgun, a welder to cut and open doors, a shoulder lamp, and a hacking device to break into computer systems.