Plot: Globulation 2 is a real-time strategy game, available in beta as of January 2009. The game updates on an irregular release cycle and is available in many Linux distribution's package repositories. The game minimizes gaming micromanagement by automatically assigning tasks to units. Wikipedia
Plot: Armagetron Advanced is a multiplayer snake game in 3D based on the light cycle sequence from the film Tron. It is available for Linux, macOS, Microsoft Windows, AmigaOS 4 and OpenBSD as free and open-source software. Wikipedia
Plot: Netrek is an Internet game for up to 16 players, written almost entirely in cross-platform open-source software. It combines features of multi-directional shooters and team-based real-time strategy games. Wikipedia
Plot: Scorched 3D is a free and open source artillery game modeled after the MS-DOS game Scorched Earth. Scorched 3D offers a new game-play approach compared to the 2D original, such as: fully destructible ... Wikipedia