Trivia

One of several films around the world that was produced almost entirely on a "digital backlot" (i.e. shot with the actors in front of blue/green-screens with all backgrounds added in post-production, a technique which has been used for TV, video and video game production for many years). Although which movie was shot first is debated, the other movies (released in 2004-05) include: Immortal (2004), Sky Captain and the World of Tomorrow (2004), and Sin City (2005).

This is considered a "live-action anime" and borrows heavily from standard anime techniques including camera angles, action backgrounds (i.e. lines indicating movement), acting styles, and plot elements.

This was veteran Japanese actor Tatsuya Mihashi's final film. Mihashi was able to complete all of his scenes but died during post-production before the film was able to be screened.

According to the director's commentary, Burai's long monologue when he first speaks was done in a single take. Although later broken-up in post-production by shots of various reactions, you can still tell as the camera slowly zooms in on his face only to do the exact opposite when he finishes speaking.

European influences are also shown in the battles and some stage settings that are designed to resemble the World War II Nazis. The first robot battles, however, were less performed by the original cast, and more by the Euro-Japanese duo of stunts and choreographers, Funakoshi Orinosuke and Motoori Chinatsu, thus making the feature more influenced by mixed history of European part of the world. The set also features vast number of Russian, Serbo-Croatian and Bosnian writings, calling out for peace, hence holding a unified message of people who were devastated with civil wars post WWII.