The player controls a sentient spaceship named Opa-Opa who fights an enemy invasion in the titular group of planets.

[2] The game design and main character have many similarities to the earlier TwinBee, and both are credited with establishing the cute 'em up subgenre.

It is possible to upgrade Opa-Opa's weapons, get bombs and flying engine to increase speed, and get extra lives.

To do these, the player must get money by defeating enemies, bases or bosses, and access a shop by touching a marked balloon.

The powerups can also be reassigned by reentering the shop or touch a balloon with the word "Select" written on it.

Fantasy Zone was re-released as an enhanced remake for the PlayStation 2, again in the Sega Ages series.

Although similar in appearance to the arcade version (even incorporating the original arcade sounds), this version uses polygons instead of sprites and adds some stages, including bonus levels with the viewpoint behind Opa-Opa as he tries to collect coins from any boss that was defeated at the moment; this game mode is very similar to Space Harrier, or the unreleased Space Fantasy Zone.

This version was released in North America and Europe as part of the Sega Classics Collection.

[5] On September 18, the final Sega Ages disc was devoted to the series, Fantasy Zone Complete Collection.

A 3D port of the game was released on March 19, 2014 for the Nintendo 3DS titled 3D Fantasy Zone: Opa-Opa Bros. New features of the 3DS port involve stereoscopic 3D visuals, adjustable difficulty settings, the ability to save the game, the ability to switch to the Japanese versions and US versions of the game, a Stage Select feature, and a new mode which involves the player playing as Upa-Upa, Opa-Opa's brother.