Godzilla vs. Gigan (Japanese: 地球攻撃命令 ゴジラ対ガイガン, Hepburn: Chikyū Kōgeki Meirei Gojira Tai Gaigan, lit.

The film stars Hiroshi Ishikawa, Yuriko Hishimi, Tomoko Umeda, and Minoru Takashima, alongside Haruo Nakajima as Godzilla, Kenpachiro Satsuma as Gigan, Koetsu Omiya as Anguirus, and Kanta Ina as Ghidorah.

The aliens assume the forms of dead humans and work as the development staff of the peace-themed theme park, World Children's Land, the centerpiece of which is "Godzilla Tower".

The Nebula M aliens plan to use the space creatures Gigan and King Ghidorah, guided by two "Action Signal Tapes", to wipe out human civilization.

Taking note of the Champion Matsuri Festival Reissue of Ghidorah, the Three-Headed Monster in 1971 and Invasion of Astro-Monster in 1972, which drew in strong attendance of 1,350,000 people (whereas Godzilla vs. Hedorah had 400,000 people), Tanaka felt the best way to reinvigorate Godzilla was not to try new things, but bring back fan-favorite villain King Ghidorah.

The Space Monsters: Earth Destruction Directive (ゴジラ対宇宙怪獣 地球防衛命令, Gojira tai Uchū Kaijū: Chikyū Bōei Meirei) involved Miko, an alien being resembling a large brain, intends to conquer the Earth using King Ghidorah, Gigan, and Megalon (later to be reworked into the main villain in 1973's Godzilla vs. Megalon).

Miko uses the three space monsters to install his being into a giant statue of Majin Tuol, a fictional Inca god, which has been erected at Tokyo's Science Land.

In addition to those stock tracks, several themes composed by Ifukube for the Mitsubishi Pavilion at Expo '70 are used throughout the movie.

A new song called "Godzilla March", sung by Susumu Ishikawa and composed by Kunio Miyauchi, plays at the end of the film.

Mizuki was contacted in early 1971 by Toho production manager Masao Suzuki to design a space monster for a new Godzilla film.

[7] Following the film's release in Japan in March, 1972, Toho commissioned Hong Kong broadcaster and voice actor Ted Thomas to produce an English language dub.

As was usual with Toho's international export versions of its films, Godzilla vs. Gigan was left uncut, although the credits were changed to English.

In 1977, Mel Maron's Cinema Shares International Distribution purchased the North American rights to Godzilla vs. Gigan and released the film as Godzilla on Monster Island in the U.S.[8] Rather than going to the expense of dubbing the film again, Cinema Shares utilized Toho's English dub.

[9] Aiming for a "G" rating from the MPAA, the company's editors removed three instances of blood from the monster scenes and muted the phrase "You're a hard bitch" on the soundtrack.

Shortly thereafter, the Sci-Fi Channel began broadcasting Cinema Shares' version, Godzilla on Monster Island, in the early 1990s.