Desktop/Android/HTML5/iOS Java game development framework
Cross-Platform C++ 2D/3D game engine
2D game development library for Ruby and C++
LÖVE is an awesome 2D game framework for Lua
Enigma is a puzzle game
Orx: Portable Game Engine
A 2D scrolling platform shooter, inspired by Duke Nukem 1
TX Library is a tiny graphics library for Win32 written in C++.
A free 3D game engine to create games and realtimes scenes for Windows
Delphi : VRCalc++ OOSL & + (Paged List, TextEditor, VRAstroVision ...)
A 2D multiplayer space shooter game
2D Platform remake based on the game from the 1980s
VR Mosaic - C++ Builder Applet v.2.5
2D Open Source MMORPG
Android apps.
Atic Atac Spectrum Game Remake
New Sabreman's adventure. New remake of a 80's game by igcefo
The library needed to make all those games true
Vivid is a modern C++ 3D engine using OpenGL4+
2D Game Engine
A cross-platform 2D game engine