Immerse yourself in the intense world of counter-terrorism. Half-Life: Counter-Strike includes Counter-Strike--the massively popular online action game built as an add-on for Half-Life--and multiplayer components from Half-Life expansions, Opposing Force and Team Fortress Classic. Team-based gameplay casts you in the role of terrorist or counter-terrorist, competing against each other throughout a variety of game scenarios. You and your team have access to real-world ammunition and equipment, and at the end of each successful mission, there's the chance to upgrade your gear.