Jorge's comic-book shop set was staged in the Usera district, Madrid. People in the street suddenly were eager to enter, hopefully believing that a real comic-book shop had opened in Usera; and, when they were told it was just a set, they refused to be disappointed arguing that there were real comic-books in the shelves. Particularly children refused to leave, and the director had a hard time explaining the situation.
Many of the characters in the movie are named after famous Spanish comic book publishers that have had the rights to publish DC, Marvel and others in Spain and México: Novaro, Vid, Bruguera, Vertice and Norma. The residential complex Victor Vid lives in is named "Surco", another Spanish publishing house that carried Marvel titles in the early 80's.
Cameo: At the beginning of the film, the deliveryman resembles Stan Lee doing one of his famous cameos.
Among the superheroes secret origins that inspired crimes in this movie are: Hulk, Iron Man, Batman, Human Torch, Spider-Man, and the X-Men.
The cover of the comic book that Jorge and Paco take turns at stealing from each other throughout the film, "Neal O'Neil vs. Zinco", is based on the iconic cover for "Superman vs. Muhammad Ali", by Neal Adams and Denny O'Neil - published in Spain by Ediciones Zinco, which published numerous other DC titles in the 80s and 90s.