After that, the player explores an abridged version of Hidden Palace Zone that is devoid of obstacles, which is followed by the final battle against Super Mecha Sonic, an Emerald-enhanced version of Sonic's robotic rival, on Sky Sanctuary Zone. The Knuckles campaign takes place shortly after Sonic's story and features the same levels up to Lava Reef Zone. When Eggman shows his true colors by stealing the Emerald and electrocuting Knuckles when the latter tries to interfere, the echidna finally realizes the doctor's trickery and helps Sonic chase after the Death Egg before it can leave orbit. Sonic's campaign culminates in a battle against Knuckles just outside the Master Emerald's altar.

The game ends with Sonic preventing Eggman's Death Egg from launching, which causes it to plummet into a volcano cone. When Sonic and Tails arrive to investigate the now seabound landmass, the former is attacked by the island's guardian, Knuckles, whom Eggman has tricked into believing that Sonic and Tails are thieves who are out to steal the Master Emerald. The island is able to fly due to its connection with the Master Emerald, a mystical gem of immeasurable power which Eggman intends to steal in order to fuel his space station. Robotnik/Eggman crash lands on the mysterious Angel Island, a Floating Continent in the middle of the sea. Following the destruction of the Death Egg, Dr. The plot picks up after the Genesis/Mega Drive version of Sonic 2.

It was the first Sonic game to offer save files. Knuckles the Echidna, an eventual member of the series' Power Trio, made his debut in this game as an antagonist. As in Sonic 2, players can control Sonic the Hedgehog, Miles 'Tails' Prower, or both. Sonic the Hedgehog 3, originally released on February 2, 1994, covers Sonic's arrival at Angel Island and his journey to Launch Base Zone. It was so ambitious that time and hardware constraints forced them to split it into two separate games: Sonic 3 & Knuckles is Sega's third 16-bit entry in the Sonic the Hedgehog series, and the follow-up to the wildly-popular Sonic the Hedgehog 2. The One With Lock-On Technology & Knuckles.

Launch base zone act 1