A retro game engine for Python
Free, open source game engine online
Open source clone of the Age of Empires II engine
RPG Maker 2000/2003 and EasyRPG games interpreter
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Powerful, mature open-source cross-platform game engine for Python
3D game engine/framework in C, with Luajit and Python bindings now
GemRB is a portable open-source implementation of the Infinity Engine
A game engine for console based text games
DOOM / Heretic / Hexen source port with enhanced graphics and UI
Python ctypes module for the Irrlicht Engine SDK
KlayGE is a cross-platform open source game engine
Turn Based Game Engine (GMS GML)
Javascript adventure game engine
Scripting language of the hawk game engine
Browser game engine
The Lambda-Engine is a cross platform game engine.