Kyuiin is a horizontal shoot-'em-up set in a fairy tale world. The players control a boy (and a girl in 2-player mode) who flies around on a vacuum cleaner fighting an array of fairy tale characters like Snow White, The Big Wolf, Frog Prince etc. In addition to a standard primary attack there is an ability to suck up certain enemies and projectiles into the vacuum thus building up a special power. Once activated this special power sends back all enemies that have been sucked in into a beam of energy and it grants a short period of invincibility. There is also a backfire cannon helpful against enemies attacking from the left side of the screen. If the boy is hit once he loses all his weapon upgrades, and a second hit destroys the boy.