I think Sonic 1 and 2 are garbage.
Sonic 1 has the most awful difficulty spikes in existence. One minute you get the fast and fun Green Hill Zone, and the next you get the incredibly slow-paced platforming emphasizing Marble Zone, and then it goes to Spring Yard Zone, which is a mix of the two, but is generally easier than Marble. The difficulty should start low with GHZ and slowly begin to get harder instead of the awful spike straight at Marble. Some of the level design in Sonic 1 is also quite dickish, and makes you wonder what mastermind decided to fuel rage into the hearts of many. Not to mention there's no save system, or continues, and the special stages are the trippiest thing ever when you spend a while playing them.
As for Sonic 2, the level design is bad, it has zones for the sake of having zones(was Oil Ocean necessary?) and does have good music, but some of it isn't as good as Sonic 1's, not to mention the change in music for Hidden Palace. Hell, even the "remastered" Hidden Palace suffers from the same design issues that the rest of the game suffers from. In terms of difficulty spikes, they're nowhere near as harsh as in Sonic 1, and the reward for collecting all of the emeralds is wonderful. The bosses are much more entertaining to fight, although some of them are just too damned hard compared to other ones in the game(Death Egg Zone, I'm talking about you) and have put me into endless save file reload loops due to running out of lives. It must be miraculous how people were able to play this game without a save system o_O.