10. Tesis (Thesis) (1996)
Alejandro Amenábar's shoestring-budgeted debut feature tells the story of Ángela, a student writing her thesis on audio-visual violence who comes into the possession of a legitimate snuff film. She seeks the advice of fellow classmate Chema (who has an extensive collection of ultra-violent movies) just as she begins to feel an attraction to Bosco (another peer who seems to be harboring some dark secrets).
Much of the movie is about unravelling the mystery of the MacGuffin snuff (MacSnuffin?) film, which minus a jump in logic here and there works pretty well. Ángela and Chema quickly begin to realise that by gathering information about the tape(s) theyre putting themselves in real danger. The problem is the double twist: Bosco is the killer and Chema has known Bosco all along. A lot of improbable things lead up to these multiple reveals but the climax is what really destroys the credibility of this story.
Too many coincidences, too much secret keeping for maximum impact. Add to the fact the snuff-film factory is actually in Ángela's school and you've officially suspended the audiences suspension of disbelief. Don't worry though - Amenábar only got better with great dark films like Abras Los Ojos and The Others.