Open source clone of the Age of Empires II engine
An OpenGL RTS game engine written in C
fheroes2 is a recreation of Heroes of Might and Magic II game engine
A game engine powered by python and panda3d
Magic Another Game Engine
The Ren'Py Visual Novel Engine
Powerful, mature open-source cross-platform game engine for Python
A retro game engine for Python
3D game engine/framework in C, with Luajit and Python bindings now
Ct.js is a desktop game engine that makes learning programming fun
A fresh & lightweight javascript game engine
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
GemRB is a portable open-source implementation of the Infinity Engine
Game engine supporting many 3D/2D formats and graphic effects
Pycraft is an open-source, OpenGL based game made in Python
A cell-based puzzle game featuring classic and completely new puzzles
PyCAPGE - Python Classic Adventure Point and Click Game Engine
Game framework with AI
Free, open source game engine online
Haskell game engine library for roguelike dungeon crawlers
A game engine for console based text games
State Management and Multiplayer Networking for Turn-Based Games
Opensource crossplatform Fallout 2 game engine writen in C++ and SDL
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.