Combat Arms is an online multiplayer first-person shooter game developed by Nexon. It is set in a modern warfare environment, where players customize their characters and compete in various game modes. Players can choose from a variety of weapons, customize their characters, and join a variety of game modes like Free-for-All, Team Deathmatch, Capture the Flag, Search and Destroy, and Quarantine. The game also features various maps and objectives. Combat Arms also includes a social network feature that allows players to join clans, view their friends' profiles, and even create their own clans. It also features an in-game currency system that allows players to purchase various items and upgrades.
Discontinued No more updates since January 2013: http://sauerbraten.org/. 2013, like Alien Arena, warned discontinued.
Discontinued development is not stopped, but the latest version, 0.8.8, was released in February 2012.
Discontinued No further updates since November 2013: http://assault.cubers.net/ (like Alien Arena, also noted to be discontinued).