The story begins when Sonic defeated Dr. Robotnik’s, this time he and his Death Egg machine fell on Angel Island, where he encountered Knuckles and tricked him, causing him to fight Sonic. While Sonic and Knuckles fight, Robotnik quickly fixes the Death Egg and also steals Master Emerald that Knuckles protects. Knowing that he had been tricked, Knuckles went to fight Robotnik but was electrocuted and stuck with Sonic in a cave. Now they are together to stop the crazy doctor’s plan. In terms of gameplay, this part is no different from Sonic 3, only the character Tails is not available and you can only choose between Sonic and Knuckles. The game is divided into many different levels, alternating between levels you will have to confront the bosses. After passing some levels, the characters can also jump higher. In addition, there will be different cutscenes depending on the character you choose. This is also a game that allows you to connect to two other versions, Sonic the Hedgehog 2 or Sonic the Hedgehog 3 thanks to the “lock-on technology” feature.