Sonic & Knuckles

Sonic & Knuckles is a 1994 platform game developed and published by Sega

Dr. Eggman's (AKA Dr. Robotnik's) Death Egg was once again blasted by Sonic, crash-landing on the peak of a volcano on the Floating Island. Dr. Eggman is still at large, and Sonic can't allow him to get his hands on the Master Emerald and repair the Death Egg. Sonic must also keep Knuckles off his back but Knuckles has problems too. As guardian of the Floating Island and all the Emeralds, Knuckles must do his part to keep the island safe. While they're going the rounds with each other, who will stop Dr. Eggman? Sonic & Knuckles features lock-on technology that allows it to combine with cartridges for both Sonic 2 and Sonic 3 in order to make Knuckles playable in both of those games.