Team Fortress

Team Fortress is a team-and-class-based online multiplayer video game mod based on id Software's Quake. Team Fortress was designed and written by Robin Walker, John Cook and Ian Caughley in 1996. The mod's gameplay has caught on with a large following of fans, which has spurred many developers to create similar gamemodes on other engines. In August 1999, after the development team was hired by Valve, Team Fortress was ported to Valve's GoldSrc engine in the form of Team Fortress Classic. An official sequel developed by Valve Corporation was hinted at for many years, and was finally released in October of 2007 as Team Fortress 2.

Team Fortress Classic
Released in April 1999, Team Fortress Classic, also known as Team Fortress 1.5 or simply TFC, is a team-based multiplayer first-person shooter video game developed by Valve Corporation. It is a remake of the Team Fortress modification for Quake. Team Fortress Classic was originally released for Windows on April 7, 1999 as a free addition to Half-Life. A standalone version was later released with Valve's Steam system in 2003. The development of Team Fortress Classic was led by John Cook and Robin Walker, the designers of the original Team Fortress modification.

The game was originally announced in 1999, powered by Valve's GoldSrc engine. The designers of the Team Fortress modification were contracted by Valve to develop Team Fortress 2, but initially remade their original work on Valve's game engine. The game itself involves a number of teams, each with access to nine classes, competing in a variety of scenarios such as capture the flag, VIP protection and territorial control. In June 2000, the game underwent a significant upgrade, adding new player character models and game modes. As of 2008, the game is one of the ten most played Half-Life modifications in terms of players, according to GameSpy.

Team Fortress 2
Team Fortress 2 (abbreviated as TF2) is a free-to-play team-based first-person shooter multiplayer video game developed by Valve Corporation. A sequel to the original mod Team Fortress based on the Quake engine, it was first released as part of the video game compilation The Orange Box on October 10, 2007 for Windows and the Xbox 360. A PlayStation 3 version then followed on November 22, 2007. The game was later released as a standalone package for Windows on April 9, 2008, and for Mac OS X two years later. Team Fortress 2 is distributed online through the Steam system, while retail distribution was handled by Electronic Arts. In June 2011, the game became a free-to-play title, supported by microtransactions for unique in-game equipment through Steam. The development of Team Fortress 2 is led by John Cook and Robin Walker, the designers who originally created the Team Fortress modification for Quake in 1996.

The game was announced in 1998, powered by Valve's GoldSrc engine, but has since been through various concepts and designs. In 1999, the game appeared to be deviating from its predecessors by pursuing a more realistic and militaristic style of gameplay, but the design metamorphosed over its nine-year development period. The final rendition sports cartoon style visuals influenced by the art of J. C. Leyendecker, Dean Cornwell and Norman Rockwell and is powered by the Source engine. The game itself revolves around two teams, each with access to nine distinct characters, battling in a variety of game modes set in evil genius environments.

The lack of information or apparent progress for six years of the game's original development caused it to be labeled as vaporware, and it was regularly featured in Wired News ' annual vaporware list among other ignominies. Upon its release, the game received critical acclaim and several awards, being praised for its graphical style, balanced gameplay, comedic value and for its use of full character personalities in a dedicated multiplayer game.