Here's my opinion (which is the one that counts):
Sonic 1 - Best Sonic game evar. I just wish they would have waited a couple of weeks to release it so we could get the scrolling clouds in the first level, the extra layers in the second level and the line scrolling water like the Japanese did. Still gets a bit tiresome after extended periods, though.
Sonic 2 - Second best Sonic game evar. Many improvements, but overall it did seem to basically be more of the same (repetition). However this game shows off the Genesis' super-powerful interlace mode which needs to be seen in order to be believed! Wow! Amazing! Incredible! 320x448 resolution from a home console! I can't believe we haven't put a man on Mars yet with this kind of sheer power.
Sonic 3 - This had some nice things going for it, but I felt the character art took a HUGE hit. Look at the title screen. Just look at it! Look how awful it is. Is that even Sonic? It looks like an unlicensed stuffed animal or something. Music was good, but it lacked the character that the first 2 Sonics had.
Sonic & Knuckles - This is pretty much a more boring version of Sonic 3 with worse music. Never let anyone named "Howard" do your music. When combined with Sonic 3, you get a Sonic game that is entirely too long, however this is remedied by the save feature. Speaking of the save feature, it must be seen to be believed! Knuckles didn't have a battery, and neither did the Sonic 3 cart! How did they save their data? Through space-age technology! The save data will never go away. Again... man on Mars & Sega Genesis. Who else sees the connection?
Sonic CD - This could have been good, but the framerate hiccups quite a bit and the time-traveling feature really bores me to tears. It also breaks the flow of the game. Music is great, though I really hate the first stage music in the US version. God damn hippies.
Sonic Spinball - This game is enough to make any Sega fanboy switch to anyone else. It's horrible!
Sonic 3D Blast - Only the mighty Sega Genesis can deliver a game with this kind of power. Not only did it travel to the future and steal music from Sonic Adventure on the Dreamcast, but it has Axelay scaling! Wait... it gets better!!!! The Axelay scaling is even better than Axelay!!!!!!!!! I bet this game has already been on Mars
Knuckles' Chaotix - This game is odd but actually really cool once you get used to it. I think most people were expecting a regular Sonic game which they already had ad nauseum on the Genesis. Best music of the series! And polygonal bonus stages that will blow your mind with the extreme technology used. I was about to make a Mars comment again, but then I realized that the 32X's code name is Mars! They harnessed the power of the entire planet Mars into the 32X to give us such a fine gaming achievement. I need to go wipe myself.
