SDI - Strategic Defense Initiative

SDI: Strategic Defense Initiative is a multi-genre action game set during an alternate Cold War in October 2017, where the USSR never collapsed and extremists have seized control of missile installations. You command a US space defense station tasked with protecting American cities and the orbital shield from periodic nuclear attacks. The game alternates between two distinct gameplay modes: an offensive side-scrolling shooter where you pilot a satellite, moving with the joystick and independently aiming a crosshair; and a defensive "Missile Command" style section where you intercept incoming warheads before they reach their targets. Successfully destroying all enemies in the offensive phase skips the defensive phase entirely.

Master System

Released in 1987 in Japan and 1988 in western territories under the title Global Defense . Developed internally by Sega . The Master System version required significant compromises to adapt the arcade's unique dual-control scheme (joystick + trackball) to a standard control pad. The player must hold a button while moving the D-pad to switch between moving the satellite and aiming the crosshair—making simultaneous movement and aiming impossible . An alternate two-controller configuration is available: the first controller aims while the second controls movement, with auto-fire enabled . Graphics and audio are reduced compared to the arcade original, and the difficulty is lowered to accommodate the control limitations . The western release features new cover art and carries the Global Defense title . A competent if compromised conversion of a technically ambitious arcade shooter.