Metal the Hedgehog is a hack of Sonic the Hedgehog where Sonic and Tails are replaced by Metal Sonic and Charmy Bee. Made by Kampfer.

Ray the Flying Squirrel in Sonic the Hedgehog is a fan-made ROM of the game Sonic the Hedgehog for the Sega Mega Drive/Genesis, featuring the character Ray the Flying Squirrel in place of Sonic the Hedgehog, the game's usual protagonist. The creator of the hack is Fabricechaotix.Ray the Flying Squirrel has a air glide move similar to Knuckles but the air glide does no damage when touching enemies. The air glide also does not stop when touching walls. Unlike many Sonic 1 hacks there is no spin dash move.

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.