The film was nearly banned in Japan due to the fact that the makeup that some of the characters wore as they were turning into humanoid mushroom creatures was very reminiscent of how many Japanese people looked after the atomic bombings of Hiroshima and Nagasaki.
Steven Soderbergh wanted to remake this film, since it had frightened him as a child. Unfortunately, he could not reach a deal with Toho and the remake was never made as a result of this.
The film's shipwreck set was designed to be tilted, which assistant director Kôji Kajita recalled made him feel sick after standing all day on it.
Although they were established stars at Toho, actors Kumi Mizuno and Yoshio Tsuchiya had no qualms about their involvement in genre films. Mizuno had work for acclaimed directors such as Naruse, Inagaki, and Okamoto. Tsuchiya was recognized for being one of Akira Kurosawa's favorite actors and cited how he enjoyed working in science fiction films just as much as in Kurosawa's films. Mizuno cited this as her favorite of all of the tokusatsu films that she was involved in.
This was director Honda's first film for Toho after a lengthy layoff and actor Tsuchiya remembered him being very enthusiastic about the project.