Revealing mistake: Throughout the movie (for instance, at its first appearance when it drives towards the camera, or when it drives off), Sonny Chiba's vehicle (or rather, its shell) is made of cardboard; the front creases, the fins wobble.
Visible crew/equipment: As the man walks down the corridor, before being asked for a match, on the left wall there is a shadow of the boom, and briefly the sound man holding it. (00:16:25)