Think of it as the more fun, much more enjoyable sequel to the other threads.
Another thing I remember. I had gotten my hands on a copy of the first Sonic the Hedgehog game, but I was told it didn't work. I figured maybe it'll work in my Genesis, but try as I might, the SEGA logo would not show itself. With that said, I went back to Sonic 2. Not long after that however, my Sega plug was fried. It was left on for a long time while the plug was sitting under some clothes that were on the floor. I can honestly say I don't remember who left it running or how the clothes ended up on top of the plug. The Genesis was in my parents room at the time, and I have 4 siblings, 2 older and 2 younger. The point is, I couldn't play Sonic or any Genesis game for that matter, not for years anyway. Of course, today I have the first Sonic for a few different consoles as well as a working Gen 2 with plug.
I was told once that I could substitute a Nintendo plug for the Sega, well, that would have worked for a Gen 1, but the Gen 2 has a smaller input along with the Gen 3. I believe the Game Gear has the same plug as well.