What the fuck is everyone talking about, SA2 is a pretty simple 3D action game.
There was no need to change the actions with the Y button during normal gameplay..
And what about Sonic 3 which had a ton of gameplay changing power-ups, various special stages, various characters, snowboarding parts, that casino level jump thing that everyone gets stuck on..
If I really want to argue about this I'll start complaining that in Sonic 3 you have to use button combinations and timed presses to spindash at full speed.
And I had lots of fun with Knuckles stages, that's a matter of opinion. I n«know people that love Eggman stages and I found them boring. Overall the gameplay was diverse and balanced.
EDIT: Health bar?