Valve Corporation (commonly referred to as Valve) is an American video game developer and digital distribution company headquartered in Bellevue, Washington. The company is known for the Half-Life, Counter-Strike, Portal, Day of Defeat, Team Fortress, and Left 4 Dead series, Dota 2, and its software distribution platform Steam.
After the success of Half-Life, the team worked on mods, spin-offs, and sequels, including Half-Life 2. All current Valve games are built on its Source engine. The company has developed six game series: Half-Life, Team Fortress, Portal, Counter-Strike, Left 4 Dead and Day of Defeat. Valve is noted for its support of its games’ modding community, most prominently, Counter-Strike, Team Fortress, and Day of Defeat. Valve has branched out with this tradition to continue developing Dota 2 as the standalone sequel to the Warcraft III mod.Each of these games began as a third-party mod that Valve purchased and developed into a full game. They also distribute community mods on Steam.Valve announced the Source 2 engine in March 2015, later porting the entirety of Dota 2 to the engine in September of that year
Valve worked with Arkane Studios on The Crossing, which was canceled in May 2009. Arkane later tried to produce Return to Ravenholm (a.k.a. Half-Life 2: Episode Four) without consensus by Valve, which was then also canceled