Sonic the Hedgehog 3 is a 1994 platform game developed by Sega Technical Institute and published by Sega for the Sega Genesis. Like previous Sonic games, players traverse side-scrolling levels while collecting rings and defeating enemies. They control Sonic and Tails, who attempt to retrieve the Chaos Emeralds to stop Doctor Robotnik from relaunching his space station, the Death Egg, after it crash-lands on a mysterious floating island. Sonic 3 introduces Knuckles the Echidna, the island guardian, who lays traps for Sonic and Tails.