The source code to VVVVVV
Open source HTML5 game framework that offers WebGL and Canvas
Desktop/Android/HTML5/iOS Java game development framework
A simple and easy-to-use library to enjoy videogames programming
Open source library for creative expression on the web, desktop, etc.
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Action-adventure game originally released in 2013
Use the Delta Executor APK with Roblox on a Windows PC.
Popular Roblox executor
Examples of procedural geometry for Unity3D C#
The Atomic Game Engine is a multi-platform 2D and 3D engine
Open-source, cross-platform, C++ game engine for creating 2D/3D games
Modern AS3 Game Engine
Egret is a brand new open mobile game and application engine
Hungry Hero is an open source Flash game built on Starling Framework.