Luis Buñuel is a master filmmaker & his autobiography (My Last Sigh) is a must read for any aspiring filmmaker. Something can be learned from almost every sinlge one of his films. The Exterminating Angel was no exception.
Every aspect of this movie is filled to the brim with subtext and metaphors. It ruminates on love, class divide, and just the basic human experience, among other things. Truly there are many lessons one can take away from this film. However, the greatest gift it gives the audience is freedom from explanation.
The movie's entire premise is one which defies logical explanation. " A group of high society friends are invited to a mansion for dinner and find themselves inexplicably unable to leave." This seemingly supernatural force that keeps guests inside the house, and their would be saviors outside, is never explained, nor are its rules explicitly definied. We can infer that the guests cannot leave, but we never learn exactly why. This Bunuel leaves up to the audience.
Buñuel covered his film with a dreamlike quality that made even inexplicable actions acceptable to the audience. A mysterious hand, a wandering bear, a goat blindfolded, and strange dream sequences populate the movie. This constantly reminds the audience of the film's dreamlike tone. With the tone of his film being distinctly noticeable and fairly consistent many developments typically unseen in a "normal" film become commonplace to the audience. If the film did not have a distinct tone that drew attention to the strange, unusual, and dreamlike nature of the film's events then it would not have been as successful.
What Buñuel teaches us in this film is that storytelling is extremely flexible when matched with the correct tone. This film is able to get away with a premise that taken literally makes no sense. However when combined with metaphor and a dreamlike tone, the premise not only makes sense but becomes excellent. As filmmakers watch The Exterminating Angel they will constantly be reminded of Stanely Kubrick's famous quote "If it can be written, or thought, then it can be filmed."