The Ren'Py Visual Novel Engine
3D Engine with Blender Integration
Open source clone of the Age of Empires II engine
Vivid3D is a C++ IDE/3D engine, with python scripting.
maXbox is a script tool engine, compiler and source lib all in one exe
PyCAPGE - Python Classic Adventure Point and Click Game Engine
xSTUDIO is a high performance playback and review tool.
GameServer is a sophisticated, game server designed for online games
Cross-Platform Level Editor for Doom3 and The Dark Mod
The AWS GameKit Plugin for Unreal
Visual Novel game
Make games with Lego-like building blocks