Fantasy Zone (1991)

Originally titled "Fantasy Zone Gear: Opa Opa Jr. no Bōken", this game is technically a sequel to the first Fantasy Zone, but got released under the same name outside of Japan. Like the other Fantasy Zone titles, this is a side-scrolling shooter where you can fly through the levels in both directions, with a boss fight waiting after you destroyed all "base" enemies (they are bigger than the regular enemies and static).