It's an upcoming Sonic fan visual novel, akin to something like Murder of Sonic The Hedgehog. It's being made by JPDE Studios, the people behind games like Babelomania.

The world's a merging of canon Sonic and IDW, and lots of passion is being put behind its creation. The creator's described it as Murder of Sonic The Hedgehog meets City Hunter.

If you enjoy Sonic The Hedgehog, I urge you give this a look.

And if you like visual novels in general, I urge you to look at JPDE Studios's itch io page. They've made some genuinely incredible things.

They've also got a Patreon, where you can see exclusive art, along with earlier releases and showcases.