Luanti

Factorio-like tower defense game. Build production chains to gather more resources, and build complex facilities.

Ad-less chess server powering lichess.org, with official iOS and Android client apps.

An open source voxel game engine. Play one of our many games, mod a game to your liking, make your own game, or play on a multiplayer server.

Minimalist text adventure game for your browser.

Transport tycoon simulation game.

The Battle for Wesnoth is an Open Source, turn-based tactical strategy game with a high fantasy theme, featuring both singleplayer and online/hotseat multiplayer combat.

Unique puzzle game designed for geeks and developers, where you solve the puzzles in the game by reading and writing Javascript.

Cross-platform real-time strategy game of ancient warfare.

Add network play functionality to Rockstar North's Grand Theft Auto game series, in which this functionality is not originally found.

Open Source on Springrts engine. Zero-K is a traditional real time strategy game with a focus on player creativity through terrain manipulation, physics, and a large roster of unique units - all while being balanced to support competitive play.

Geography multiplayer game.