Fantasy Zone
The original arcade release is also included in "Sonic's Ultimate Genesis Collection" in which is an unlockable game. A 3D port of the game was released on March 19, 2014 for the Nintendo 3DS titled "3D Fantasy Zone: Opa-Opa Bros." New features of the 3DS port involve stereoscopic 3D visuals, adjustable difficulty settings, an ability to save the game, the ability to switch to the Japanese versions and US versions of the game, a Stage Select feature and a new mode which involves the player playing as Upa-Upa, Opa-Opa's brother. In addition, satisfying certain conditions during the game enables the player to confront the two "replacement" bosses from the Master System release, each entering the boss fight by literally "replacing" the standard boss.