SDI - Strategic Defense Initiative (Japan, newer, System 16A, FD1089B 317-0027)

In SDI - Strategic Defense Initiative, players take on the role of satellite commanders in a tense two-player shooter released by Sega in 1987. Working cooperatively, you must defend against waves of incoming enemy projectiles using a trackball and button controls to aim and fire. The game presents a strategic challenge requiring careful coordination as players manage their defensive satellites across multiple stages. The gameplay centers around intercepting the approaching threats, emphasizing precise aiming and tactical positioning rather than rapid-fire action. A unique "Flicky Mode" can be unlocked with a specific code, altering the player’s satellite appearance at the start of Stage 2. This title utilizes Sega's System 16A hardware and was initially released in Japan before receiving export versions under different names. SDI spawned several ports to various platforms including home consoles and computers shortly after its arcade debut. While known in Japan, an alternate version titled Defense saw release elsewhere, and both titles share a common technical foundation on the Sega System 16A.