Developed by Minh Le and Jess Cliffe, the tactical shooter was first released in beta form in 1999, and gained a sizable audience right away.
The most successful of the bunch, though, was a multiplayer mod dubbed Counter-Strike. Many, many Half-Life mods-and fuller games that started as Half-Life mods-were churned out during this period, including Deathmatch Classic, Ricochet, Gunman Chronicles and Day of Defeat. Moves like this greatly helped bolster Valves reputation amongst hardcore gamers, earning it a vocal and loyal fanbase thats still crucial to its success today. A veritable truckload of user-created mods soon spawned, and Valve helped foster more than a few of them into becoming more polished releases.
But more significantly, the late '90s and early 2000s saw Valve encourage an enthusiastic modding community around Half-Life by releasing the games software development kit (SDK) for free.
