arrow keys to move, jump at eggman, but don't get hit by that big ball he carries for no reason. pinch mode features big chase. if sonic doesn't move, then click the screen and try to move him again there is a spot where you can't get hurt, but why would I tell you where it is
For some reason there's a bug where if you attack Eggman just frames after already hitting him four times right before the pinch, it counts as a hit, and the pinch just won't occur. I can't fix it, so let me know if you know how to in the comments