A game engine powered by python and panda3d
3D game engine/framework in C, with Luajit and Python bindings now
Zig game engine & graphics toolkit
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
TurboSphere is an easy to learn and powerful JS based game engine.
Open source, moddable game engine for the "Polygon Love 2" game
The Lambda-Engine is a cross platform game engine.