Trivia

Director Yoshimitsu Banno has mentioned that Hedorah's eyes in the film were deliberately made to resemble female genitalia, with Banno joking that the vaginally inspired look made it more unsettling. During Godzilla's battle with Hedorah, strange white orbs are ripped out of Hedorah's dried-out body. According to Banno, they are meant to be Hedorah's eyes, which he considered the most important part of a person's body. The film has a running theme of eyes being injured with several of its characters. However, the reason they do not resemble Hedorah's actual eyes is due to rushed production and a smaller budget. Banno mentioned that not only had Toho given him less than half of the budget of the prior Godzilla films, but he was also only given 35 days to shoot the entire film (both the drama scenes and the special effects scenes). Making matters even more challenging for Banno was the fact that he had to make do with a single film crew.

This was the first film that featured Kenpachirô Satsuma wearing a Toho monster suit; in this case, portraying Hedorah. Reportedly, Satsuma was initially disappointed by the role, as he did not care for monster films and his face would not be visible in the suit. He accepted the job because it paid well and, over time, developed a fondness for monster suit acting, which he partially credited to the kindness displayed by special effect director Teruyoshi Nakano. Though small in stature, Satsuma was quite strong for his size and was the only one capable of supporting the 300-pound suit for long periods of time (though there were some wire works to help support it). Satsuma then went on to portray Gigan in the next two films in the Godzilla film series, Godzilla vs. Gigan (1972) and Godzilla vs. Megalon (1973). After a hiatus of over 10 years, he would be asked to portray Godzilla in the film Godzilla 1985 (1985) and would continue in the role of Godzilla throughout the Heisei series. He retired after the film Godzilla vs. Destoroyah (1995).

When Godzilla chases down Hedorah, director Yoshimitsu Banno originally shot two different scenes. One had Godzilla chasing down Hedorah on foot, the other was the famous scene of Godzilla flying after him. The flying scene was the one used in the final cut of the film because Banno thought that a comical scene was needed to lighten up the mood and to contrast the film's much darker imagery, especially of people being killed by Hedorah.

A sequel to this film which would have been set in Africa was tentatively planned. However, producer Tomoyuki Tanaka, who had been hospitalized during production, was disappointed by the finished film and supposedly even told director Yoshimitsu Banno that he had ruined the Godzilla film series. Late in his life Banno disputed this story, claiming Tanaka never got openly angry at him. Tanaka had approved the script and let Banno complete the film his way on the one condition that the studio would decide on the final cut. Tanaka even briefly visited the set where the nightclub scene was being filmed, but left immediately without saying anything. Banno only found out about Tanaka's supposed anger in an English Godzilla book from the 1990s shortly after Tanaka's death. Banno did admit the producer was somewhat displeased with the film and might have secretly feared what a sequel would be like. Tanaka then ordered the filming of Godzilla vs. Gigan (1972) instead, a more conventional Godzilla film.

This is the only film in the Godzilla film series in which Godzilla demonstrated an ability to fly by firing his atomic breath towards the ground and propelling himself backwards through the air with it.