All Your History Are Belong To Us S01 E18 Valve Part 2: Half-Life's Afterlife

From Half-Life to Left 4 Dead 2, Valve has been one of the trailblazers of the video game industry. In this second episode of our retrospective, watch and see how Valve's decision to open their code to the modding community led to a wealth of creativity and popularity, which in turn, made a successful game a smash hit.