In the window of Dog's bedroom there are four robot toys: C3PO and R2D2 from the Star Wars franchise, Robbie the Robot from El planeta desconocido (1956) and Mazinger Z from the TV series Majingâ Zetto (1972).
As there is no dialogue in the movie, voice actors are credited but not associated with a determined character. They don't speak, just make sounds. However, it is known that voice director and actor Ivan Labanda voices both Dog and Robot.
Dog lives above "Chicken and Cat," which is the title of another Sara Varon book.
Dog's surname in the film is shown to be 'Varon'. This is a reference Sara Varon, the author of the graphic novel upon which the film is based.
Dog carries a bag in the early portions of this film which has a logo on it. That logo is Naranjito the mascot for the España '82 Football World Cup. A nod to Director Pablo Berger's homeland.