[5][6][7] According to Tomoyuki Tanaka, Mechagodzilla was inspired by both Mechani-Kong from the previous Toho film King Kong Escapes and the robot anime genre, which was popular at the time.

[8] Effects director Teruyoshi Nakano also felt that a mechanical monster was cheaper to construct than the mutated animals Godzilla had previously faced.

Mechagodzilla's design remained largely unchanged from its previous appearance, though it was made to look thinner and more angular, with a darker sheen and an MG2 insignia emblazoned on its upper arms.

Special effects artist Koichi Kawakita originally envisioned Mechagodzilla being able to split into aerial and terrestrial units, though this idea was scrapped in favor of the character merging with the flying battleship Garuda.

The film was promoted through the children's program Adventure Godzilla-land, which portrayed Godzilla and Mechagodzilla as rival news anchors reporting on the events of the upcoming movie.

[15] Composer Akira Ifukube wrote a theme for Mechagodzilla incorporating a slow battle march with heavy percussion and pentatonic phrasing.

Tezuka had initially wanted Mechagodzilla to be a much speedier robot than the one on film, envisioning it as becoming progressively more agile during its fight against Godzilla as the latter tore off its opponent's armaments.

[16] In the 2003 sequel Godzilla: Tokyo S.O.S., creature designer Shinichi Wakasa used the same mold to create a redesigned Mechagodzilla, which was meant to look more weathered than its predecessor.

As the previous design's shoulder cannons were considered uneven and unsophisticated-looking because of their rectangular shape, special effects director Eiichi Asada made them more pentagonal.

[21] The upgraded model featured in Terror of Mechagodzilla included revolving missiles, and was no longer vulnerable to decapitation, as its main computer was housed in an external power source.

[22] The Heisei Mechagodzilla stands at 120 m (390 ft) in height, weighs 150,000 metric tons, and is powered by a nuclear reactor which derives its energy from heavy hydrogen and helium-3 in pellet form.

Its frame is coated in an armor made of synthetic diamond codenamed T-1, allowing the robot to resist and repel Godzilla's atomic breath, as well as absorb its power to energize its Plasma Grenade, an energy weapon housed in its abdomen.

[23] Kiryu, the Millennium Mechagodzilla, stands at 60 m (200 ft) in height, weighs 40,000 metric tons, and is piloted remotely from a control craft.

The mecha can be remotely recharged from the ground using microwaves that are relayed through a power system on one of the command aircraft, and then beamed back down to the robot.

Its most powerful and most energetically costly weapon is the Absolute Zero Cannon housed in its chest, which fires a beam capable of flash freezing enemies.

[25] The Anime Trilogy Mechagodzilla stands 50 meters in height, weighs 30,000 metric tons, and is powered by artificial intelligence and made from nanometal.

In the novel: Project Mechagodzilla, its arsenal includes a Blade Launcher, Convergent Neutron Cannon, Flight, Hyper Lance, Thermal Energy Buffer Layer, and Tail Blow.

When it forms Mechagodzilla city, the defenses include gun cannons, EMP Harpoons, and a force field to protect itself when fired upon.

Their initial battle results in a tie, as Godzilla is severely wounded and Mechagodzilla is forced back into the Simian's base for repair.

During its first battle with Godzilla four years later in 2003, Kiryu's genetic memories of its 1954 incarnation are awakened, and it proceeds to attack Tokyo, free from the controls of its pilot until its power drains.

In Godzilla: The Planet Eater, some nanometal survives within Yuko's body which Professor Martin extracts and applies to the last Vulture intending to rebuild civilization.

However, the process unexpectedly allows Ghidorah's mind to possess Mechagodzilla, who then kills both Simmons and Serizawa, goes on a rampage in the city, and faces Godzilla.

As Mechagodzilla maintains the upper hand, Josh Valentine tampers with its control panel via alcohol spillage, stalling it long enough for Godzilla to supercharge Kong's axe with his atomic breath.

The protagonists, tied up in the building by Yakuza thugs, witness Godzilla rampage through the game's setting, the fictional Ichi City, and Kiryu is eventually deployed in response.

The newspaper that displays the results after the level reveals that, after 30 minutes of rampaging, Kiryu has run out of power, allowing the government to retrieve the inactive mecha.

The Shōwa, Heisei, Anime Trilogy, MonsterVerse Mechagodzilla, and Kiryu appear as playable characters in Godzilla Battle Line.

[27] A Shōwa-inspired Mechagodzilla appears in the post-credits scene of the anime series Godzilla Singular Point, though the lab's computer screens identify him as Robogodzilla.

15 of the 50 Best Movie Robots by The Times, beating other such legends as C-3PO from Star Wars, the T-1000 from Terminator 2: Judgment Day, and Optimus Prime from Transformers.