Like Ecco, I generally just keep Tails in the back, and I've memorized the stages enough that I can time the jumps so Tails doesn't get hit.
I've played way too much Sonic 2, I know. :P
There's that one special stage in S&K that always got me, even though it's really not all that hard.
Never. I always used cheats. Sonic 2's special stages will always remain as my least favourite. Sonic 3's on the other hand, are great. I enjoy the challenge from them. Especially when they speed up. Hell yeah.
Then again I did put in ungodly hours into Sonic 1 & Knuckles/Blue Spheres as a kid, so I got really good at it.
Just ran through these Special Stages today with Sonic for old time's sake. With Sonic only. Got all the emeralds by the end of the 1st Zone. I always found the Special Stages on Sonic 2 to be the easiest tbh, followed probably by Sonic 3 and Sonic 1. Have always hated the ones on Sonic CD, but then again Sonic CD is my least favorite Sonic game.
I personally don't get the love for Sonic CD at all. I just beat that game for the second time ever, and thus ending my Sonic marathon with it on a low-light. Granted, I didn't even bother trying to get the emeralds in Sonic CD, or figure out the past/future gimmick. I just wanted it to be over as fast as possible. And because of this I'm unable to look deeper into what makes this game tick. My least favourite level was the one where the entire bottom of the stage was a spring board. Man the level designs in Sonic CD drove me foaming at the mouth. :D
I did cleared Sonic 2's special stages without level select. I memorized them so much that I was able to clear them at first try the least few times I've played the game xD
Regarding Sonic CD, I too don't understand the praise. It's beautiful but to me it seems unpolished. The special stages are the most frustrating, the time travel mechanics felt unnecessary, and the stages were mostly weird in terms of level design.
I did, but it wasn't easy.