If you cheat & or put in the time to get all the chaos emeralds in the

sonic 3 cartridge

combined with

the sonic & knuckles cartridge

for sega genesis then the game becomes extremely easy

After you beat sonic 3 with all 7 emeralds you can next collect an additional 7 emeralds for the knuckles level

If you play as sonic you get an even more powerful double version of super sonic

Tails and knuckles get single super versions

Super Tails or knuckles or double super sonic make it too easy