Sonic 3 + Knuckles imo, but idk how much of it is because everyone seems to think sonic 2 is better

3k has more content, better graphics, and a better special stage. the only point i can give 2 is that its sonic sprite is better, and that's negated by a.i.r. mods

i like sonic 2 better, but im biased since i played it when little

Sonic 3

I prefer Sonic 2