The third film in the series is essentially a more modernised reworking of the story of the second film, with some more of the art-house influences present in the 1989 Tetsuo: The Iron Man. The visual effects are refined and the 'Tetsuo' design is more complex visually, and the film itself has a considerably higher fidelity than the grainy film used in the original two films. However, by transitioning to digital film, there is a quality in the original films that is lost, namely the dirty roughness reminiscent of rust, a theme very significant to the first two films. The Bullet Man is a more chaotic affair than Body Hammer but lacks of the black humour of The Iron Man, resulting in a film that is less certain of itself perhaps than it's predecessors.
Tsukamoto's work is often concerned with transformation or the transformational effect of emotions, often rage, on a person. Tokyo Fist (1995) is similarly concerned with anger and violence, infused with a great deal of the black humour present in the first Tetsuo film. In A Snake of June (2002), the main themes are voyeurism and malaise, with the main character a woman in an interminable marriage that is completely sexually repressed, who inadvertently inspires a photographer to 'save her' the way she saved him through a sort of Samaritans hotline. He does this by blackmailing her into exploring her sexuality, threatening to send on photographs of her masturbating to her husband if she doesn't comply.
Tsukamoto stars in all of these films, and would typically be considered an auteur as he writes and directs most of his work, occasionally taking direction only projects. This would indicate that these roles that he plays (the antagonist in all three Tetsuo films, the photographer in A Snake of June and the anti-hero in Tokyo Fist) have great significance to him.
Man-machine physical transformation (American actor Eric Bossick) in Tetsuo: The Bullet Man
Shinya Tsukamoto in Tetsuo: The Bullet Man
Promotional artwork for Tetsuo II: Body Hammer
Promotional artwork for Tetsuo: The Bullet Man