
Mothra faces off against several of Toho's iconic monsters, including Godzilla, in Monster's Fair.
The game begins with the Shobijin being captured by a UFO, crying out "HELP, MOTHRA!" It then starts with Mothra in her larval stage emerging from an egg. She has the ability to fire webs that can stun most monsters, with the exception of Godzilla and Hedorah. Mothra can move in all directions—north, south, west, and east—but once she moves upward, the screen locks, preventing her from returning to areas that have scrolled off the screen. Mothra can only withstand five hits before being defeated, and players are given three lives. Hidden power-ups that restore health are scattered throughout the game, but they must be revealed by shooting them with web before they can be collected. Players can earn additional lives by accumulating 30,000 points.