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 CD
The Sega CD supports a library of over 200 games created both by Sega and an array of third-party publishers. Included in this library are six games which, while receiving individual Sega CD releases, also received separate versions that utilized both the Sega CD and 32X add-ons. Among the games released for the add-on were a number of FMV games, including "Sewer Shark" and "Fahrenheit". Well-regarded games include "Sonic CD", "" and "", "Popful Mail", and "Snatcher", as well as the controversial "Night Trap". Although Sega created "Streets of Rage" for the Genesis to compete against the SNES port of the arcade hit "Final Fight", the Sega CD received an enhanced version of the latter game that has been praised for its greater faithfulness to the arcade original. "" was noted for its impressive use of the system's hardware as well as its violent content. In particular, "Sonic CD" garnered critical acclaim for its graphics and new time travel elements, which improved upon the traditional "Sonic" formula. The Sega CD also received enhanced ports of games from the Genesis, such as "Batman Returns" and "Ecco the Dolphin".