The movie's from 1967 and its main theme leans heavily on surf rock, which is a definite bonus. It has Japanese vocals in combination with the surf guitar and drums with some of the more martial music conventions commonly found in Japanese sci-fi and anime scores of the time.

There's another song, a tender ballad called "Good Luck, Baby Gappa", which sure makes me hope that Gappa is the hero of the movie. For some reason, I've never seen it or at least don't remember it.

Island exotica music is also well represented, in cues such as "Landing", "The Islanders", "Welcome Dance" and "Fire Dance".

"The Stone Statue/The Cavern" sounds very much like what you would hear in a Godzilla movie around the same time, both in its composition and arrangement.

The influence of Akira Ifukube's work might have played a part in some of the more somber and/or heavier cues such as "Baby Gappa Airlift Operation" and "Baby Gappa to Haneda Airport", although the instrumentation is not like Ifukube for the most part.

This typically great release from Cinema-kan also has some extras including trailer music and a sound effects collection.