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".
History of Sega
To compete with Nintendo, Sega was more open to new types of games than its rival, but still tightly controlled the approval process for third-party games and charged high prices for cartridge manufacturing. Technicians from American third-party video game publisher Electronic Arts (EA) reverse engineered the Genesis in 1989, following nearly one year of negotiations with Sega in which EA requested a more liberal licensing agreement than was standard in the industry before releasing its games for the system. As a result, EA signed what founder Trip Hawkins described as "a very unusual and much more enlightened license agreement" with Sega in June 1990: "Among other things, we had the right to make as many titles as we wanted. We could approve our own titles ... the royalty rates were a lot more reasonable. We also had more direct control over manufacturing." The first Genesis version of EA's "John Madden Football" arrived before the end of 1990, and became what EA creative officer Bing Gordon called a "killer app" for the system.