I've updated the Unstdio website and the 2D game engine is now available for download. It's definitely in an alpha stage, so as soon as I get some time to continue work on it some of the classes may change. There are also some classes that are currently there as placeholders, and not currently used (for example, GameMenu).
If you find anything wrong, definitely email me and I'll be sure to fix it as soon as I can. If you modify the code and add any features, I would very much appreciate those being made available to myself and everyone else, but that isn't required. Definitely do not claim ownership of the engine, and if used, please give credit where it's due.