The fact that a beautiful film like No mires para abajo receives a rating as low as this can only mean that most people simply cannot look past the explicit depiction of sex and nudity on film. It's a shame, because aside from being quite erotic, it's actually a beautiful and sensitive film, a piece of magical realism in the finest tradition of South American authors like Márquez and Borges, and it deals with the organic and spiritual links between life, death and sexuality with no attempt to create controversy or to arouse in the usual sense, but rather to create an atmosphere of magical, dreamy bliss.
To be fair, No mires para abajo gives only a glimpse into the dreamworld it describes; the film is very short, very small in scope, and it probably wouldn't have worked had it been longer - it's an image, rather than a complete story. The two main characters are intriguing, lovable and mysterious, but neither one is a full and complex character. But for what it is, it works beautifully. It's not a story with a beginning, a middle and an end; there's no arc, or character development, or conflict. It's just a beautiful short glimpse into a more beautiful side of our reality, and if you can look past the sex and nudity and enjoy it for what it is, it's highly recommended. It won't be to everybody's taste, to be sure, but it should never be dismissed as softcore porn.