 Some Half-Life modifications eventually landed on retail shelves. Counter-Strike was the most successful, having been released in six different editions: as a standalone product (2000), as part of the Platinum Pack (2000), as an Xbox version (2003), as a single player spin-off called Counter-Strike: Condition Zero (2004), Counter-Strike: Source, which runs on Half-Life 2's Source engine, and the newest addition Counter-Strike: Global Offensive, also running on the Source engine. Team Fortress Classic, Day of Defeat, Gunman Chronicles (2000, a futuristic Western movie-style total conversion with emphasis on its single player mode) and Sven Co-op were also released as stand-alone products.
