To achieve sonicknuckleswsonic3bin extra quality , you cannot simply download the first file you find on a sketchy pop-up site. You need the "No-Intro" standard.
To get "extra quality" out of the file (the combined ROM for Sonic 3 & Knuckles ), the industry standard is to use Sonic 3 A.I.R. (Angel Island Revisited)
The standalone Sonic 3 introduced Chaos Emeralds, and Sonic & Knuckles introduced Super Emeralds. Only in the combined game do these two mechanics merge. By collecting the Chaos Emeralds in Sonic 3, players could upgrade them to Super Emeralds in the Hidden Palace Zone (accessed via the Sonic & Knuckles half). This allowed players to unlock , Hyper Knuckles , and Super Tails —power-ups that provided end-game rewards that were actually worth the grind.