Sonic the Hedgehog (ソニック・ザ・ヘッジホッグ Sonikku za Hejjihoggu?) is a platform video game developed by Sonic Team and published by Sega for the Sega Mega Drive/Genesis. First released in North America, Europe, and Australia on June 23, 1991, the game is the first installment in the Sonic the Hedgehog series, chronicling the adventures of the titular character in his quest to defeat the series' antagonist Dr. Robotnik. The game's story focuses on Sonic's efforts to stop Dr. Robotnik's plans for world domination, release the animals Dr. Robotnik has trapped, and collect six magical emeralds known as the Chaos Emeralds.Development of Sonic the Hedgehog began in 1990, when Sega ordered its AM8 development team to develop a game featuring a mascot for the company. After a hedgehog was decided on as the main character, the development group was renamed Sonic Team.Sonic the Hedgehog received positive reviews from critics, who praised the game's visuals and its sense of speed. It was commercially successful, increasing the popularity of the Mega Drive/Genesis and establishing Sonic the Hedgehog as the company's mascot. Its success led to the development of subsequent games in the Sonic the Hedgehog series, as well as the creation of a media franchise of spin-off products featuring the character.

Sonic the Hedgehog refers to the Sonic the Hedgehog video game series released by Sega, and starring its eponymous mascot, the video game character Sonic the Hedgehog. The video game series is the primary product in a multimedia franchise, including products in a wide range of media.

Sonic the Hedgehog refers to the Sonic the Hedgehog video game series released by Sega, and starring its eponymous mascot, the video game character Sonic the Hedgehog. The video game series is the primary product in a multimedia franchise, including products in a wide range of media.

Sonic: The One Ring is a hack of the original Sonic the Hedgehog game for the Sega Mega Drive / Genesis, created by Mercury. Its defining (and titular) feature is that in each Act, all rings but one have been removed, and Sonic cannot complete the Act without this One Ring in his possession. Thus, in each Act, Sonic must search for the One Ring that will afford him the opportunity to progress. Several alterations have been made to the game, to somewhat balance the lack of rings, and allow backtracking during the search.