AssaultCube is a free, open-source first-person shooter game that focuses on realistic combat simulation. It is set in an open environment, where the player must use their weapons and skills to complete various objectives. It is designed to be as realistic as possible, with realistic weapons, physics, and animations. It has online multiplayer capabilities, as well as offline options, such as single player mode. The game is set in a variety of locations, such as a desert, a forest, and a city. It also has several game modes, including deathmatch, team deathmatch, last man standing, and capture the flag. The game also features a variety of weapons, ranging from pistols to assault rifles. Additionally, the game features a variety of vehicles for the player to utilize in order to traverse the environment.
Discontinued No more updates since January 2013: http://sauerbraten.org/. 2013, like Alien Arena, warned discontinued.