Odamex is a free, cross-platform, modern client-server Doom engine
0 A.D. is a free, open-source, cross-platform real-time strategy game.
GameServer is a sophisticated, game server designed for online games
A fun realistic multiplayer free-and-open-source first-person-shooter!
A free 3d game for PC that does not limit the player. Fight,Build,Gain
Visual Basic 6 2D online adventure game engine
FreeCS is a free-software reimplementation of Counter-Strike 1.5.
oGame-like browser space realtime strategy game based on xNova
An open-source, multiplayer fps based on Cube 2 Engine.
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
Text Browser-Based MMO is a project with with forum integration.
Cosmos Tycoon is a open source transport simulation browser game.
starrydb is game server engine
Clone of Urban Assault with new Graphics.
JAVA websocket implementation for a bomberman-like game
Grepolis utility
A collection of all maps and games made for the TripleA game engine
Java decentralized cross-platform network multiplayer game engine
Free strategy browsergame engine.
Your death sentence awaits...
3D FPS Digital Paintball 3 Multiplayer Online Game