Toilet Kids(1992)

Toilet Kids is a vertical shoot 'em up featuring a world filled with scatological enemies and humor. It was released exclusively on the PC Engine. A young boy is accidentally flushed town the toilet one night, appearing in a mysterious world, and must defeat the world's guardian before he can go home. The game has four stages total, each of which has a different theme, and the player is able to target both air enemies and ground enemies in a system similar to that introduced in Xevious.