Open source clone of the Age of Empires II engine
Real Time Strategy game engine supporting early Westwood classics
Arianne is an engine to develop multiplayer online games like Stendhal
Europa Universalis 4 save game editor
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
Mech Station Beta - Tower Defense like Game
Open source FPS/RTS Game
A simple gui game that plays the game bagels with users.
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
Open source revival of the game Transarctica / Arctic Baron
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.
The Python/Tk Empire Interface
A Wargame
A game engine in java for 2D strategy games