Sonic 2, first appearance of Tails, some new changes to gameplay. And is yet another classic to play.
You got more stages, music, new gameplay elements. Music, i think is the worst of the series, some of the music don't sound like a Sonic game at all. It sounds more like a racing game or an action game on teh NES. It's hard to explain.
This game offers a pointless multiplayer mode, which can be fun at times, be sometimes downright boring. But hey, i wasn't born in 1992, so, what do i know about 16-bit? ...plenty.
It's basically got the same things the first one has, but with some improvements. And, above all, check it out. It's one game you won't forget playing.
oh, and just ignore Tails would you?