Sonic 3 and Knuckles [Genesis] (Knuckles) Longplay 1994

Angel island has come crashing down into the ocean! It looks like Dr. Robotnik has stolen the Master Emerald that keeps the island floating. Knuckles, who is responsible for guarding it, must chase the evil Doctor down to get it back. What evil plans does Dr. Robotnik have for the Emerald? What will become of Angel Island? Will Knuckles be able to get it back in time?