* HeyItsThatSound: An example for King Caesar, whose roar is a recycled version of Kong's roar from ''Film/KingKongVsGodzilla''.
* KeepCirculatingTheTapes: Up until the release of the [[Creator/TheCriterionCollection Showa-Era films box set]], this was one of the hardest to get Godzilla movies for a long time due to the original DVD going out of print.
* RecycledSoundtrack:
** Several tracks, the Okinawa theme itself is recycled from the main title theme of ''Film/BattleOfOkinawa''.
** Additionally, King Caesar's battle with Mechagodzilla features the music piece of Godzilla vs. Kumonga from the film, ''Film/SonOfGodzilla''. This comes as no surprise since the composer of this film is also composed the music from the latter film as well.
* PopCultureUrbanLegends: ''Film/GodzillaVSMechagodzilla'' (1974): A rumour stated that Anguirus replaced Baragon in this film due to Anguirus displaying traits commonly associated with Baragon (IE: burrowing, great leaping ability). This rumour was attributed to the poor quality of the suit (due to how many times it had been modified for use in ''Series/{{Ultraman}}'', a factor that also precluded Baragon having any worthwhile involvement in ''Film/DestroyAllMonsters''), because Baragon was never considered for the film and early drafts of the script clearly have Anguirus as the intended monster.
* WhatCouldHaveBeen: This film had actually gone through two separate drafts until finally reaching the final product.
** The first one had the [[SarcasmMode rather lovely]] title of '''Giant Monsters Converge on Okinawa! Showdown in Zanpamisaki.''' In this draft, a malevolent race of aliens known as the Garuga's (who are described as ape-like, which stuck around till the final draft with the Black-Hole 3 aliens) who attempt to TakeOvertheWorld and sell it to the highest bidding. In order to do this, they create a robot named Garugan beneath Zanpamisaki. Godzilla, Mothra and Anguirus would've teamed up to stop the mecha unit.
** The second draft, '''Showdown in Zanpamisaki: Godzilla vs. Mechagodzilla,''' gets us a bit closer to the final product. In this draft, the Garuga's are replaced by a group of aliens simply known as the "R Aliens", who not only send out the titular Mechagodzilla, but also.. [[Film/GodzillaVsGigan Gigan!]] Godzilla and Anguirus confront them in Okinawa, where they are joined by the ancient guardian King Balgan. However, Gigan, like Mothra before him, was dropped, Balgan was reworked into King Caesar, and Anguirus was DemotedToExtra.
----