Filmed in 4 weeks, between November and December 1979.
Director's cameo: he is the crazy interviewee who appears for a few seconds in a straitjacket.
In the supermarket scene you can see an advertisement for Colomo detergent ("wash whiter"). Filmmaker Fernando Colomo was the art director for this film.
Fernando Trueba's directorial debut.
First film of Óscar Ladoire, Antonio Resines and El Gran Wyoming.
El Gran Wyoming: Thug with sun glasses who asks Matías for drugs.