A web-based IDE for HTML5 game development. Powered by Phaser
Cross platform SDK
A complete framework for Godot to create beautiful and complex AI
a 2D Game Development Framework
3D .NET engine for Windows, Linux, Mac
The Flixel Power Tools are a set of plug-ins for Flixel 2.5+
Cross platform 2D game creation framework with Python bindings
StarlingPunk is a framework built on top the Starling library
A C++ Implementation of the MIT OpenBlocks Java Code