I don't know much about the Spanish mentality and the blackest depths of Spanish souls. This movie seems to be an (unusual) account of these. I don't think the characters are completely made up by the screenwriters, only to construct a shocking story about racism. There are drunken criminals and violent skinheads in the movie - figures often appearing in films; all right. But the fact that Antonio and his family represent the ordinary lower class Spanish family with all their attitudes and manners really shocked me. The way director Uribe paints his main characters is really, really cruel. I do hope it's exaggerated.
Above all, this is an excellent movie. It creates a not customary tension most of the time and mixes irony with tragedy. The photographer also did great work and caught beautiful shots of the picturesque landscape which seems a little artificial - well, dunes always do. Only the dialogues between the family members are a bit unrealistic but I mentioned that already.
I gave this movie 8 stars out of 10 and if you ever spot it anywhere, watch it until the end because the final scenes are especially well-done. It's a small, great movie.