I got an emulator of this and its still one of my favourites. Although there was no save feature on this so once you got so far and so few Chaos Emeralds you'd have to start from scratch but the Wii saves the place you paused or hit the Home button on the Wii remote so you CAN get all 7 Chaos Emeralds and release Super Sonic!
Sonic 3 (& Knuckles bit aswel) are on my list to-get if they become downloadable! Don't listen to bad feedback on this, Sonic 2 is a classic and a top title!