The enormous popularity of Toho's giant monster films led Daiei to issue publicity stills showing the Pairans as gigantic creatures that towered over buildings. In the film, the Pairans are human sized.
The Pairan aliens were designed by the prominent avant-garde artist Taro Okamoto, which used a single eye that is common among science fiction aliens.
This was the first color tokusatsu science fiction film produced in Japan. It beat Toho's science fiction spectacle, Ishirô Honda's Prisonnières des Martiens (1957) (the first tokusatsu film in widescreen), into theaters by a year.
This film wasn't released in the United States until 1967.
The film was one of many early Japanese monster films quickly produced after the success of Toho's Godzilla (1954) in 1954. The film was loosely based on a novel by Gentaro Nakajima.