GemRB is a portable open-source implementation of the Infinity Engine
A retro game engine for Python
Open source clone of the Age of Empires II engine
A game engine for console based text games
Pycraft is an open-source, OpenGL based game made in Python
DOOM / Heretic / Hexen source port with enhanced graphics and UI
The second demo of my game engine.
Tactical, turn-based game engine, that uses OpenGL and WinAPI
Open source, moddable game engine for the "Polygon Love 2" game
Browser game engine
The Lambda-Engine is a cross platform game engine.