Sega Ages 2500 Series Vol. 21: SDI & Quartet: Sega System 16 Collection

As the name suggets, this game is a compilation which includes the Sega System 16 and Sega Master System (both Japan and worldwide) versions of SDI: Strategic Defense Initiative and Quartet. In the case of SDI, this marks the first time the game has been brought to the home with the correct dual-joystick control scheme.