Seamlessly play through both games.
Once you’ve mastered the basic menus, try these power-user moves: sonic 3 complete customizer
Before diving into the customizer, it is important to understand what is being customized. is a comprehensive ROM hack of Sonic 3 & Knuckles developed by the Sonic hacking community. Its primary goal is to present Sonic 3 and Sonic & Knuckles as one seamless, intended package, fixing bugs, restoring original features, and offering maximum compatibility. Sonic 3 Complete offers: Seamlessly play through both games
What the Customizer is trying to do, and why it matters restoring original features