Since this was a full-scale production, Toho required the use of all of their own visual effects soundstages. However, during filming of a special effects scene, a pyrotechnical accident caused a fire that burned down part of the main visual effects soundstage, an incident that was very widely reported in Japan at the time. The fire destroyed a number of costumes and props from earlier Toho tokusatsu classics that were kept in storage at the time, including the original Mogera costume from The Mysterians (1957).
During the film's initial release, scenes (including the notorious climactic mutant scene and the cannibal attack in New Huinea) received hard criticism, so Toho ended up selling a cut version to overseas markets. The film showed up once on Japanese TV in early 1980 before being pulled from circulation altogether. Toho also tried to release the film to VHS and laserdisc in the late 1980s, but the release was canceled (although an employee released a print to the black market.) The film is not banned, as is often reported - Toho simply appears to be afraid of releasing it in Japan because of the offensive nature of several key scenes. Apparently the film is for sale to U.S. distributors for DVD release. It seems unlikely that a U.S. DVD, if produced, will include the original 114 minute Japanese cut.
Was the highest-grossing domestic release of its year.
The film was never given an official home video release in Eastern Europe (primarily Ukraine and Russia), due to the protests of Chernobyl survivors.
The film takes place in 1835 and 1999.