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".
Sega Technical Institute
Sega Technical Institute (STI) was an American development division of Sega. Founded by Atari veteran Mark Cerny in 1991, the studio sought to combine elite Japanese developers, including Sonic Team programmer Yuji Naka and his team, with new American talent. STI developed a number of "Sonic the Hedgehog" games, as well as other games for the Sega Genesis, before it was closed at the end of 1996.