TX Library is a tiny graphics library for Win32 written in C++.
Game/Scene Development System
Vivid3D is a C++ IDE/3D engine, with python scripting.
OgreWin3D
High-efficiency minimalist C++ wrapper for OpenGL 4.3
A free 3D game engine to create games and realtimes scenes for Windows
Utility for viewing ZX Spectrum emulator snapshot files.
Portable game engine with main focus on point-and-click adventures
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
Lego Island 2 Game Editor
IRB is a game creation toolkit
A starter development kit that let you develop FF6-like games on PC.
Gaming library
2D game engine for traditional platform games
MMOG Framework. Starting place to build a game.
evolution for vegastrike SpaceSim/Combat/Trade game
Animation graph editor.
Cross platform 2D/3D game engine written in C++11 & OpenGL ES 2/3
Multimedia asset management and manipulator for Étoilé
A generic 2D engine for any kind of game