Real Time Strategy game engine supporting early Westwood classics
Open source clone of the Age of Empires II engine
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Arianne is an engine to develop multiplayer online games like Stendhal
Europa Universalis 4 save game editor
A free 3d game for PC that does not limit the player. Fight,Build,Gain
Open source FPS/RTS Game
Mech Station Beta - Tower Defense like Game
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
The forever free, ad-free and open source chess server
A space race game in the style of A Dark Room
A snarky 2D management game about building and running a dungeon.
Free strategy browsergame engine.
Classic Dune. Modern Controls.
A powerful chess engine written in C++
A Wargame
A game engine in java for 2D strategy games