This is the second game Sonic game on Genesis/MegaDrive. While it's not the best Sonic game, it is the most addicting.
Sonic 2 has always had some of the best level design of any Sonic game. You can tell hard work was put into making this game's levels, as many of them are put together very intracately. The scenerey is just plain pretty. If you aren't blazing through the level, you're stopping to check out the view.
The sound: Do I really have to mention how great it is? Oh, yes, I am reviewing this game, so I take it I should. The music in every level pumps you up and keeps you going, and unlike games that don't utilize their music well, this game made a point with its music. The music and level design seem to tell a story, it's almost too beautiful to be put into words. Whether you are jamming to Chemical Plant, or beatboxing to Metropolis, each level's theme is a great tune not just to help the level move along, but to be listened to altogether.
The new move added, the Spin Dash, is one of the most useful moves ever created in a Sonic game. Need a speed boost? Spin Dash. Wanna make sure you don't get hurt while moving along the level? Spin Dash. It was a useful move and the obstacles added that made you need it were simply clever.
I have only one complaint with this game. There were cheap deaths. Not water. The water was fine. But there were levels where it was either a tad too easy to get crushed, or there was a pitfall you couldn't get out of. My evidence: in Mystic Cave Zone, there was a part where if you didn't make the jump correctly, you fell to a spike pit, and there was no way up. If Sonic Team wanted you to die, they should've took the spikes out altogether.
However, the minor annoyances only show up once in awhile, and the fun to be had is timeless.