I thought that before, but it may have been the particular game. Like, Maximum Carnage's music sounded SA-WEET on SNES but worse on Genesis; however, I think that Genesis actually generated sound instead of just samples, which may have given it an advantage. On the other hand, some tracks on SNES were shitty, depending on the game. I may be wrong, but I always thought of SNES as better, but Genesis was good, depending on the game.
Oh lord, a lot. Well, parts of Sonic 2 annoyed me but it's not a bad game. You can even appreciate some of the aspects of the newer games by looking at the beginning. Like, I do like Sonic Adventure 2, but I can see the reason why I LOLed at the supposed seriousness of it. The soundtrack was excellent and the challenge was awesome, but again, artistically, the Sonic Team was starting to do too much.
Sonic 3
Gameplay: more interactive than a lot of games, even Mario. Now, the preference between Mario and Sonic lies in the appearance and feel of the game itself (which for some, Mario wins). The interaction is pretty different too.
Sonic's move were simple, but you could use your environment as well as the items. The difference with Mario was that the only attack/defense you had against enemies apart from weapons was jumping, and that only worked with some enemies; Sonic didn't have much wither but he could spin dash, somersault, jump and use that crappy-ass spinning air strike move that sux bawls.
Tails and Knuckles did the same, except that in place of that crappy-ass spinning air strike move that sux bawls, Tails could swim and fly (if Tails hit enemies below w/ his... tails, they'd get hit); Knuckles had more strength in place of jumping height; he glided and could climb.
Music: AHAHA! Whew! Well, the notes match and clash here and there (comparisons), but the main idea is to hear the swagger, even if there's clashing.
Carnival Nights Zone/Jam
Marble Garden Zone/Thriller
There are more, so just type in "Michael Jackson Sonic" in the query.
Super forms: I admit, they are ripoffs from Dragonball (Z). I'm sorry, their super forms beat Mario's star/invincibility/size increment by a mile. However, Tails' form is the best as well as the most unique. Reason is, for Sonic and Knuckles, all you needed were Chaos Emeralds (for Hyper forms you'd need Super Emeralds); for Tails you needed Chaos AND Super Emeralds to attain a higher form.
Despite opinions, the older Sonic games gave you more freedom with the super forms; in the latter games, it's all "Sawnik savez da day huray". I dug the Super Sonic/Shadow combo in Sonic Adventure 2 + Shadow's fight with Biolizard, but still: what if you could go through the game as Super Sonic?
Extra talk: To be honest, some things are better about Sonic's newer games while others are better about the older ones, but once you get to Sonic Heroes, Sonic becomes wack. Sonic went to Hell. Yes, straight to H-E-double hockey sticks in gasoline drawers.
I did beat Sonic Heroes, but Jesus, what'd they do? They went from Snowboarding and Grinding Sneakers to THIS SHIT? No... I enjoyed the first part, got a headache at the Chemical Plant and literally lost my sanity playing the spinball levels. I'll tell you, the best pinball simulation was in Sonic Spinball and Sonic Adventure 1. Sonic Heroes turned spinballing into a 3-D visual fuckup. Some of the levels such as Hang Castle and the Team Dark fight against Eggman were AWESOME, but the game execution... bad. And Metalsonic? What the fuck did they do to him? Sonic Team failed so hard.