Sonic 3 & Knuckles: Pro Survivor it's an palette and layout hack; the point on this one it's to have a extra difficult and hard layout (though fair), with some improved gimmicks.
In the last year, I wasn't very happy with the state of the hack, so this one I decided to give it a better effort and polish everything with my best effort (with new content, of course)!
Unfortunately, it's still just a demo and not a full version. So the 5 only levels available are:
Angel Island Zone, Hydrocity Zone Act 1, Ice Cap Zone, Flying Battery Zone and Sandopolis Zone (unfortunately too, AIZ and ICZ2 isn't ready yet for Knuckles, so I hope you understand).
Also, has a new Main Menu and a New mode (up to you unlock), and in the future will have more features.
Now let's go to the credits.
Credits
Hack Author, Layout and Level Design:
*NeoFusionBox Team