While adapting the story for the film, screenwriter Shinichi Sekizawa picked his favorite aspects of the story and ignored everything else. Sekizawa patterned his script after the original "King Kong" and "Godzilla" films. Sekizawa felt that too much detail will confuse audiences and that it was more important to keep audiences entertained, stating, "My philosophy is to just add enough to tell the story and keep it moving along." Honda later admitted that the fantasy elements were Sekizawa's ideas while Honda was interested in the anti-nuclear themes. Originally, Hotta wanted to include an anti-discrimination message based on a person's size.