: Built on the Source Engine , the same technology behind Half-Life 2 .
Released in 2006, this first-person shooter was intended to be the first of a nine-part series, though it remains the only episode ever released .
: A single playthrough typically lasts between 3 to 6 hours . 💻 System Requirements
: Built on the Source Engine , the same technology behind Half-Life 2 .
Released in 2006, this first-person shooter was intended to be the first of a nine-part series, though it remains the only episode ever released . : Built on the Source Engine , the
: A single playthrough typically lasts between 3 to 6 hours . 💻 System Requirements : Built on the Source Engine