* ExecutiveMeddling: See below, where Kamoebas was originally going to be Anguirus.
* WhatCouldHaveBeen:
** The role of a dead monster who washes up ashore having had its throat slit by Godzilla was originally going to be a giant ''Liopleurodon'' but Toho decided against it, feeling that it wouldn't have made much sense to make a new monster just to kill it off. Anguirus was then suggested, but Toho wanted to keep him alive in case of a future entry. (it should be stated that Final Wars probably wasn't said entry as they wanted to continue the Kiryu saga at the time) Frustrated, Tezuka then suggested ''Gamera'' to be the one laying dead, but Toho said Kamoebas from ''Film/SpaceAmoeba'' was good enough cause they don't own Gamera.
*** Toho then considered having Godzilla kill Anguirus ''again'' in "Final Wars" but budgetary restraints saved him.
** [[AllThereInTheManual Supplemental material for the film]] suggests the [[TheStinger Kaiju DNA Freezer]] would be used to create more cyborg kaiju and escalate into a full-out [[TurnedAgainstTheirMasters Mecha Apocalypse]].
** Tezuka was apparently given four different story outlines to choose from for the film, but he found them all boring and wrote his own that ended up being the final version.
** Tezuka also submitted a draft for a potential solo Kiryu film some time after production on this film wrapped, but it never came to be.
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