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 Team
The "Sonic the Hedgehog" project began with just Naka and Ohshima, but grew to involve two programmers, two sound engineers, and three designers. Yasuhara joined to supervise Naka and Ohshima and develop levels, and became the lead designer. He satisfied Naka's request for a simple, one-button design by having Sonic do damage by jumping. "Sonic the Hedgehog" was released in 1991 and proved a major success, contributing to millions of sales of the Genesis. The development team took the name Sonic Team for the game's release. Naka has referred to Sonic Team as only a "team name" at this point.