It's obvious to me that Toho took a strong cue from the Gamera films from this point on. They started using stock footage, which the Gamera films were already notorious for (Destroy All Planets has that godforsaken entire reel of clips from the previous three films just to pad the runtime), precocious Japanese boys in hot pants became the protagonists and Teruyoshi Nakano even started using cartoony blood n' guts in his kaiju sequences just like Yuasa.