PyCAPGE - Python Classic Adventure Point and Click Game Engine
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
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A distributed graph deep learning framework.
CSG for jMonkey
XNA based game engine completely written in c#
3D Interactive sandbox environment
2D Game Engine, based on OpenGL and focused on Isometric Games
A cross-platform OpenGL based lightweight scenegraph library
A cross-platform Java 2D graphics library using OpenGL.
A simple WinAPI game engine