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 Forever
The initial wave of games were from Sega's Genesis/Mega Drive, Game Gear, and Master System platforms, although they plan on adding games from the SG-1000, Sega Saturn, and Dreamcast platforms as well. During the testing phases of the system, Saturn and Dreamcast games did not perform satisfactorily, though Sega has on-going R&D efforts working on improving them in hopes of future release. Games such as "Panzer Dragoon" are being considered for the service, but could not be successfully emulated in the testing phase, meaning that such a release would hypothetically require a lengthy porting process instead. Sega is also open to releasing games that had not previously had English localizations, such as the Yuji Naka-designed game, "Girl's Garden".