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Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux. The project is geared towards providing addictive arena shooter gameplay which is all spawned and driven by the community itself. Xonotic is a direct successor of Nexuiz with years of development between them, and it aims to become the best possible open-source FPS (first-person-shooter) of its kind.

Aion is a visually stunning MMORPG where your character wields devastating powers and sweeping wings to explore a celestial world.

Alien Swarm is a free top-down shoot-em-up video game by Valve Corporation. It is a remake of the Alien Swarm mod for Unreal Tournament 2004, and it was developed by the original team, which was hired by Valve during the course of the development process.

Eternal Lands (EL) is a free, multiplayer, online role-playing game (MMORPG) created by Radu Privantu in 2002. The setting is a medieval fantasy world. There are historic elements such as medieval architecture and weaponry along with fictional elements such as other humanoid races and magic. It is made of up two main continents: Seridia and Irilion in the world of Draia. Seridia is the first continent, and the place in which new players spawn. It consists of 14 main maps, 7 storages, 2 main PK maps, and the only spot to find the Wraith. Irillion is directed towards experienced players. »

The Hammer of Thyrion project is a cross-platform source port effort of Raven Software's Hexen.

The Mana World (TMW) is a serious effort to create an innovative free and open source MMORPG. TMW uses 2D graphics and aims to create a large and diverse interactive world. It is licensed under the GPL, making sure this game can't ever run away from you.

Alien Arena is a free and opensource first-person shooter game that combines a 1950s-era sci-fi atmosphere with gameplay similar to Quake (series) , Doom (Series) and Unreal Tournament (series) . Alien Arena focuses mainly on online multiplayer action, although it does contain single-player matches against bots.