Woah boy, here comes a series of my opinions that some people might disagree with!
I was fortunate enough to grow up in a household with both a SNES and a Genesis. There is a distinct stylistic difference between first party Sega and Nintendo titles of that era that I can only quantify as "post-arcade" and "proto-modern". Sega often approached game design with the arcade in mind. Quick sessions with score boards designed to breed competition and eat quarters. Sonic 1 has a lot these arcade conventions in it's DNA. The timer, the score, the 1 button controls, etc. Speed was a measure of how good you became at navigating these levels. The joy for me came in memorizing all the routes and being able to seemlessly travel through entire levels without stopping, but it took lots of practice to do so. It turns what is essentially just a few hours of content into a highly replayable arcade-like experience.
As we got sequels, 2, CD, 3 & knuckles, more emphasis was placed on story, larger levels, more varied power ups, and mini-games. But at it's core a traditional 2D sonic title has it's heart in the arcade.
Nintendo titles were more proto-modern in the sense that they began to chase cinematic experiences (Zelda lttp, super Metroid) and long style play mechanics. The Mario and Kirby series' seemed to cater to the whole family, while Sega was chasing the teens and young adults who grew up with the NES and SMS. This affected the marketing, thus warping perceptions of Nintendo games as being "kiddy" and Sega games as being "extreme". Many allowed bad marketing to deprive themselves of great games from both systems.
So I feel sorry for those of you who fell prey to shitty marketing gimmicks, and I would like to welcome you guys to embrace Sega's arcade roots. I hope that there is a nugget of fun you can find.