Throughout the movie, Daisato struggles with balancing his superhero duties with his personal life. He is constantly dealing with the pressure of living up to his family's legacy, as his grandfather was a respected superhero in his prime. However, Daisato's own abilities are lacking, leading to frequent defeats and public ridicule.
As Daisato continues to battle strange and eccentric monsters, he begins to question his role as a superhero and the impact he has on society. He also grapples with feelings of loneliness and isolation, as his unique profession sets him apart from others. Despite his shortcomings, Daisato remains dedicated to protecting Japan and its citizens, even if it means enduring the ridicule and criticism of those around him.
The film uses a combination of documentary-style footage and interviews with Daisato and his family to humorously explore themes of identity, family, and societal expectations. With its offbeat humor and quirky characters, "Big Man Japan" offers a fresh take on the superhero genre and delivers a heartfelt message about acceptance and self-discovery.