After a while, Sonic OSX has been officially released. It's a 2D Sonic framework in Game Maker Studio 2.3 that allows you to make your own games based on the Advance, Adventure, and Rush styles. It comes with 5 stages, 5 playable characters and 2 bosses, though it's meant for you to easily add or modify content.

Gameplay video with download link: https://youtu.be/nfVM_6-Oxgs?si=-mDi1NYTtJ2Bn_fC

The download comes with both an exe and a yyz file, the latter of which contains the source code for the framework. You will need the latest version of Game Maker Studio 2.3 and a good understanding of GML to use this framework.

Enjoy!