Quake 3 Fortress was a mod released in 1999 for Quake III: Arena, a First-Person shooter made the same year. The mod was extremely popular during its early beta, but after losing popularity after certain updates, all servers were shut down. The initial popularity of the mod led to the creation of Team Fortress Classic, its spiritual successor.
The player has to choose a class, then they enter the game. The game was mainly a Capture-The-Flag game, where the player must take the Enemy Flag and take it to their base. There are two teams, the Blue Team and the Red Team.