ET:QW is a first-person shooter game and is the follow-up to Wolfenstein: Enemy Territory. However, it is set in the same science fiction universe as Quake II and Quake 4, with a backstory serving as a prequel to Quake II. It is the second multiplayer-only game in the Quake series (after Quake III Arena). Quake Wars features similar gameplay to Wolfenstein: Enemy Territory, but with the addition of controllable vehicles and aircraft, asymmetric teams, much larger maps and the option of computer-controlled bots. Unlike the previous Enemy Territory game, Quake Wars is a commercial release rather than a free download.