It could be that you're used to the old low frame-rate of the original game.
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hobbledehoy899
MadMageKefka
Could be less imput lag too maybe? I noticed myself turning early sometimes at first. Easily adjusted, though.
SonicfanCEMUTesting
You're all wrong. It's probably because some of the new stages are more tricky than the original ones. Problem solved, goodbye.
MadMageKefka
...or maybe you're just bad at them? 
SonicfanCEMUTesting
I think not.