fheroes2 is a recreation of Heroes of Might and Magic II game engine
Open source clone of the Age of Empires II engine
Free and open source real-time strategy game
Doom-based AI research platform for reinforcement learning
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Opensource crossplatform Fallout 2 game engine writen in C++ and SDL
A 2D multiplayer space shooter game
Magical Quixo game
With the helpfull nef, you have to rescue earthlike planets!
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
OpenGL port of the classic 6dof 3D shooter Descent
Battle for Wesnoth is a turn based fantasy strategic game
Famous card game with 3D graphics and artificial intelligence
A simple fantasy game
A minimalist multiplayer game inspired by Astro Party, for Windows.
Single-player space fighter simulation game
Turn based Civ-like strategy game