An American Werewolf in London was first released in the United States 32 years ago this month. The film will perhaps be best remembered for the stunning special effects from makeup artist Rick Baker (who received both an Academy Award and a Saturn Award for his contribution to the film) and it stands as a useful example of why the subgenre is so interesting to fans of horror films. The structural framework of the werewolf film allows for a higher level of multi-dimensionality within the characters — a higher level indeed than most other horror subgenres.
If we’re talking about a killer’s split personality providing the thrust of what keeps a film interesting, the werewolf film provides a far more satisfying set up than, say, the slasher films which employ the Norman Bates complex for at least two reasons: 1.) repressed sexual desire provides an intellectually lazy, borderline sexist, and ultimately dissatisfying motivation for murder and 2.) this dual personage typically relies on a twist ending wherein the killer is revealed to be someone we thought of as being docile and harmless the whole time — which is rarely surprising or interesting these days because of how frequently we’ve seen it, and because of how poorly executed the trick usually is (High Tension  and Secret Window  are two examples summoned readily to mind).
With the werewolf films, though, the viewer is in on the secret the whole time, and part of what keeps everything engaging is the character’s dramatic shift in both appearance and behavior when the full moon rises. Films like An American Werewolf in London and The Howling (1981) are, therefore, exceptionally engaging because the fully exploit the visual potential of the transformation sequence.
You don’t necessarily need a werewolf, however, to employ the plot devices and trickery of werewolf films. So interesting, that a number of films have more-or-less rehashed the tropes of the genre, without dealing explicitly with wolfs. The key to the werewolf film, really, is the dual personage it imposes on the character. Sometimes what’s interesting is the contrast between when the character is and isn’t the monster, and sometimes what’s interesting is that dual personage device is used to amplify and exaggerate characteristics that the character is already endowed with.
One “werewolf sans werewolf” film that springs to mind is the Italian Atom Age Vampire (1963). And don’t let the title deceive you — There’s no real vampire in the traditional sense in this one, either. Produced by Mario Bava and directed by Anton Giulio Majano, this film tells the story of a scientist (Albert Lupo) who who falls in love with one of his female patients — a professional singer (Susanne Loret) whose face is disfigured after an auto-accident. He relies on a special, custom-designed cell regenerating serum to preserve her beauty. But when he starts to deplete his resources, he’s forced to scour the streets for human victims, whose cells he harvests. He injects himself with a serum that renders him a cold, emotionless killer, so that he may go out into the streets at night to tend to his evil bidding. The film isn’t a terrific one, but employs the dual personage device successfully, and the transformation scene is an excellent one!
Another film which bears revisiting, if only for its special effects, is Philippe Mora’s The Beast Within (1982). Two newlyweds (Ronny Cox and Bibi Besch) experience car trouble while driving through a small southern town, and the wife is violently raped by a giant insect monster. Fast forward seventeen years…the couple have a teenage son Michael (Paul Clemens) who is experiencing bizarre changes…I don’t want to give away too much other than that, although I will caution you not to get too caught up in the films incoherent subplots, and appreciate it for its atmosphere, its perverse allegory for puberty, and for the mother of all eighties transformation sequences, which is unrivaled (not for its artistry, nor for its believability) but for its gratuitousness.
Don’t take my word for it though…