Open source voxel world
Combat Flight Simulator for LINUX. WW2. Network and VOIP. Open-source.
Odamex is a free, cross-platform, modern client-server Doom engine
Cooperative multiplayer graphical RPG and adventure game
0 A.D. is a free, open-source, cross-platform real-time strategy game.
A free 3d game for PC that does not limit the player. Fight,Build,Gain
Cross-platform real-time strategy game (3D)
Free and open source Avatar Webgame made by Vietnam
FreeCS is a free-software reimplementation of Counter-Strike 1.5.
A fun realistic multiplayer free-and-open-source first-person-shooter!
Free MMORPG
Free Minecraft Servers tweaked for a lag-free experience!
A massively multiplayer tank battle game.
a PHP based leaderboard software for Battlefield 4
a PHP based leaderboard software for Battlefield Hardline
Free strategy browsergame engine.
a PHP based leaderboard for World of Tanks and World of Warplanes
Free 3D Roguelike action RPG
Tongue-in-cheek action RPG
Action-packed local multiplayer game
GraphOX is awesome