Desktop/Android/HTML5/iOS Java game development framework
Vivid3D is a C++ IDE/3D engine, with python scripting.
High-efficiency minimalist C++ wrapper for OpenGL 4.3
A free 3D game engine to create games and realtimes scenes for Windows
Small lightweight program to customize your keyboard
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
A 2D game engine and level editor
Cross-platform 2D and 3D game engine
IGS Labs
Portable game engine with main focus on point-and-click adventures
Build Cross-platform Applications
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
Lego Island 2 Game Editor
Perl bindings to the Modern OpenGL API
Open-source, cross-platform, C++ game engine for creating 2D/3D games
Gaming library
3D Game Engine
Open Game Bootstrap