As a wink to the many Mazinger-Z fans in Spain, Italy and France, a brief image of the Sagrada Familia in Barcelona, Pisa tower in Italy and Eiffel tower in Paris can be briefly seen in the film.
In the English dub, Dr. Hell is voiced by Mike Pollock, who also voiced Dr. Eggman/Robotnik from the Sonic the Hedgehog game series. And like Dr. Hell, Dr. Eggman is also a mad scientist with an army of robots.