Old-school 2D game engine
Vivid3D is a C++ IDE/3D engine, with python scripting.
OgreWin3D
A free 3D game engine to create games and realtimes scenes for Windows
Vivid3D is an open-source 3D engine with powerful 2D UI.
Cinema Enters Game Console
Modern 3D engine and IDE written using C# and C++.
Portable game engine with main focus on point-and-click adventures
Javascript Canvas Framework
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
An Adventure Game Engine
IRB is a game creation toolkit
A generic framework for chess games
Gaming library
2D game engine for traditional platform games
A game engine written in the D programming language
.NET - VISUAL BASIC NVIDIA +ATI PHYSX SLIMDX DIRECTX 9 -ENGINE/WRAPPER
Simple data driven web based gamebook engine using javascript.
Unreal Engine 4 first-person criminal simulator.
An advanced flexible game engine for Java.
Cross platform 2D/3D game engine written in C++11 & OpenGL ES 2/3
THIS SOFTWARE IS IN PRE-PRE-PRE-PRE-ALPHA. So don't really download it