half-life 2 is a first person shooter video game created by the company valve corporation and released in 2004. this game is the sequel to the original half-life video game which came out in 1998. it is sold through the steam platform also developed by valve. it is also available in the orange box, along with and (sequels to half-life 2), portal, and team fortress 2. half-life 3 is currently in development. half-life 2 is based on a game engine called source. there have been many other source-based games, such as portal, team fortress 2, , and garry's mod.