106. Galaga: Demons of Death (Namco, 1988)
105. A Boy and His Blob: Trouble on Blobolonia (Absolute Entertainment, 1989)
103. Zanac (Compile, 1987)
Shoot-em-ups (generally abbreviated to "shmups" nowadays) have been around since video games were first a thing, and there is no shortage of debate about which games in that vast genre are the best. Zanac was definitely one of my favorites among those released in this era, though. Not only did it feature surprisingly fast-paced and relentless action for its time, but it was surprisingly innovative too, containing an adaptive AI that would make things progressively tougher if you were doing well or firing too many shots, or ease up if you were struggling or consistently destroyed enemy recon craft. It had quite a variety of weapons too - eight upgradable special weapons in total, plus an upgradable default gun, gave you plenty of options and firepower to deal with your foes. It's not the prettiest shooter on the system by a long shot, but it plays amazingly well, so who's complaining?
100. Astyanax (Aicom, 1990)