Aperture Tag: The Paint Gun Testing Initiative.Zeno Clash (Originally planned as a mod, then made as a retail game).Star Trek: Enterprise - Temporal Cold War.The Stanley Parable (Turned into a retail game).
Half-Life 2: Short Stories: Human Error. Garry's Mod (Turned into a retail game). Dear Esther (Turned into a retail game). USS Darkstar (Also ported to Sega Dreamcast). They Hunger (Also ported to Sega Dreamcast). Team Fortress (Turned into retail games developed by Valve). Ricochet (Turned into a retail game developed by Valve). PARANOIA (Also ported to Sega Dreamcast). Day of Defeat (Turned into retail games developed by Valve). Crazy Black Messa - Still under development. Black Ops (Also ported to Sega Dreamcast). Counter-Strike (Turned into retail games developed by Valve). The list is incomplete feel free to complete it with other notable mods. The non-commercial mods can be downloaded for free, as they are not licensing the engine. made from scratch, only using the existing engine, models, sounds, textures, etc. Some of these mods include minor or major alterations to the original game, others consist in a total conversion, i.e. Some mods are also based on cut content, featured in the released files for Half-Life, and in the leaked files for Half-Life 2. However some mods such as Garry's Mod having been turned into commercial games remain independent. Some original mods, such as Counter-Strike, Team Fortress, Day of Defeat, Ricochet, The Ship and Alien Swarm (originally a mod for Unreal Tournament 2004) have been "adopted" by Valve and made into commercial games. The Half-Life series spawned countless mods, among which many that became highly popular in the Half-Life gaming community. HD Alyx based on Brazilian model Adriana Lima in FakeFactory's Cinematic Mod, Version 8. In-game screenshot of Black Mesa, a total conversion of Half-Life to the Source engine. In-game screenshot of Sven Co-op, one of the oldest Half-Life mods to be still in development. An in-game screenshot from Cry Of Fear, one of the newest released Half-Life Mods from 2012.