is a platform video game developed by Sonic Team and published by Sega for the Sega Genesis console in 1991. The game was released in North America, Europe and Australia on June 23, 1991, and in Japan the following month. It stars Sonic the Hedgehog in a quest to defeat Dr. Robotnik, an evil scientist who has imprisoned animals in robots and stolen the magical Chaos Emeralds. Sonic the Hedgehogs gameplay involves collecting rings as a form of health and a simple control scheme, with jumping and attacking controlled by a single button.