Sonic Jam
"Sonic Jam" is a compilation which contains the four main "Sonic the Hedgehog" games released on the Sega Genesis: "Sonic the Hedgehog", "Sonic the Hedgehog 2", "Sonic the Hedgehog 3", and "Sonic & Knuckles". Unlike future "Sonic" collections, "Sonic Jam" does not use a Genesis emulator; the games are proper ports, and all are nearly identical to the original Sega Genesis releases, with the exception of minor bug fixes. "Sonic Jam" emulates "Sonic & Knuckles" "lock-on technology"—a special feature that allows the player to merge elements of "Sonic & Knuckles" into previous games, resulting in changes to the level design as well as the choice to play as Knuckles the Echidna in "Sonic the Hedgehog 2" and Tails in "Sonic & Knuckles".
Sonic the Hedgehog (8-bit video game)
In 1990, Sega released the Game Gear, an 8-bit handheld game console designed to compete with Nintendo's Game Boy. Around the same time, Sonic Team worked on "Sonic the Hedgehog" for the 16-bit Genesis and Sega wanted to increase consumer awareness of the Game Gear by producing a version of "Sonic" for the system. 22-year old composer Yuzo Koshiro had recently started working with Sega, having been asked to compose the soundtrack for the Genesis version of "The Revenge of Shinobi" (1989). After, he told a section chief he could develop games himself. As a result, a general manager, whom Koshiro met while working on "The Revenge of Shinobi", asked him to start developing a Game Gear version of "Sonic". Koshiro founded Ancient to develop the game because Sega could not make contracts with individuals. His sister Ayano Koshiro served as director and his mother Tomo Koshiro had a "behind the scenes" role, while the first programmer he hired was Shinobu Hayashi. The 8-bit "Sonic" was created specifically for the Game Gear, but Sega also had Ancient develop a version for the Master System, which was selling well and had similar hardware.