Sonic the Hedgehog 2 Tips

Easier way to beat final boss
after you beat metal sonic and follow robotnik until he jumps into his machine, go and stand near the left wall. Robotnik will walk towards you and stop, and as he bends down to lift off, hit him above his arms. He will then lift off into the air and home in on you. While he is aiming on you, rev up your spin dash and once he has established his lock, release and roll to the far right of the screen. Wait there while he shoots his arms at you, they will not hit you if you stay at the wall, and when he lifts off, repeat the spin dash manuver. He will again walk towards you and stop, hit him again and repeat the entire process until you defeat him. You can additionally sneak a hit in right after he lifts his machine out from the ground, but make sure you hit him pretty near the apex of your jump, otherwise you'll hit his spike-hands and die.