Springs, bumpers, you name it, along with the agonizingly pink background (and I LOVE pink so saying it's agonizing is something) made it not only extremely disorienting, but also kind of sickening.
Truth be told, I don't think Sonic's for me. I have too many different design philosophies to really jive with it, I like 3D slightly more, but I'm largely indifferent to the series. Not to mention, playing 2D Sonic for too long leaves me nauseous, so it's literally sickening to play.
If a game isn't just meh for me (like Sonic 2 and Sonic Adventure), then I think it's downright awful (like Sonic CD and Sonic Adventure 2). The only game I've thought was great was Generations. But since I'm on this thread...
I did pick up Sonic Advance 2 at the behest of a recent article about good SEGA GBA games, and I think it's okay. Again, my dislike of Sonic's general design keeps me from thinking it's that good, but for a portable game, I can say it's alright.