Sonic the Hedgehog 1 and 2, plus Sonic Mania as those are the ones I have touched somewhat recently. I can not remember if I played Sonic 3 & Knuckles as a kid or not, so maybe I am overly biased. In general, I have a fairly positive view of the Sonic platformers in every regard apart from the controls. The music for example is good, although it is not the best that the Mega Drive has to offer as that would probably be Thunder Force IV. Same for having very nice sprite work and the Sonic 2 bonus level blew my mind as a kid.
> Regarding my comment about the difficulty, for me it is mostly a result of the bad controls, which to be honest is a problem that plagues many games of that era. You have enemies popping out from the edge of the screen and you need to react in a fraction of a second, but the controls don't let you do so, so you need to memorize the whole game and react in advance. It is not fun for me.
Can relate, but I wonder if what you are describing here is the excessively zoomed in trend that we had from the late 80s and throughout the 90s.