George Takei's first film project.
Godzilla became such a huge hit that Toho produced this sequel and got it into theaters, despite the numerous special effects scenes required, in less than six months after the original film was released.
George Takei, better known as Lt. Hikaru Sulu in the original Star Trek series, was one of the many voice actors employed for this film. The only other Kaiju film he performed voice work for was in the Americanized version of_Sora no daikaijû Radon (1956)_.
Instead of using Masaru Satô's original score, Warner substituted themes from Kronos and The Deerslayer.
Many times during the American dubbed version, Godzilla uses Anguirus' trademark roar more often than he uses his own.
Special effects director Eiji Tsuburaya wanted the fight scenes filmed in slow motion, but a camera technician accidentally undercranked the camera instead of overcranking it, resulting in the action appearing faster than reality. Tsuburaya liked the effect, and decided to use it in the film.
The only Godzilla movie where Godzilla's spines do not glow before he releases his radioactive flame.
There have been two different stories as to why Godzilla's name was changed to "Gigantis" in the American version:
- Warner Brothers could not get permission to use Godzilla from Joseph E. Levine and had to change the name to "Gigantis".
- In an interview, Paul Schreibman, the producer of the American version, said that he changed Godzilla's name to "Gigantis" to give the audience the impression that they were seeing a new monster. He has since regretted that decision.
This is the first film in which Godzilla fights another monster.
This suit used in this movie was very similar to the first one in Godzilla, King of the Monsters. This suit was used for Godzilla's second appearance, Godzilla Raids Again. It was slimmed down to fit Haruo Nakajima better, and to make the acting process a little more comfortable. It would also allow him to make more violent moves while shooting battle scenes. The irises were much bigger than the original suit, which was a smaller, and had the "beady" look. The dorsal fins were kept about the same size, and shape as the original. There were still four toes on each foot, and the little ears were still behind his eyes. This overall appearance still gave Godzilla a look of terror, and a menace to mankind.
This was the series debuts for both Hiroshi Koizumi and Yoshio Tsuchiya. Both actors would appear in five series films. Koizumi would appear in three Showa Era films as well as one each in both the Hesei and Millenium eras while Tsuchiya would appear in four Showa films but only one in the Hesei era.
Was going to be remade in the US as "The Volcano Monsters". It followed a similar plot line where a Tyrannosaurus and an Ankylosaurus are found battling and are captured then brought to San Francisco where they awake and do battle. Unfortunately the rights could not be obtained and the movie was never made. However, many of the elements from that script written by Ib Melchior would later be used in the film Reptilicus.