Ti West's retro horror film seems to me like a more successful attempt at what Quentin Tarantino was trying to do in Death Proof, his half of the Grindhouse double-bill. Each film has a two-act structure with a slow, talky first half designed to get you interested in characters who'll end up in extreme jeopardy. But while Tarantino depended pretty much on his dialogue alone to build and maintain your interest, West does a better job building up sympathy or empathy for Samantha (Jocelin Donahue) and Megan (Greta Gerwig). He nicely establishes Samantha's isolation on the college campus and her need to get away from an obnoxious roommate, as well as the quirkiness that leaves Samantha and Megan, two otherwise attractive if not hot young women, as each other's best if not only friends. West's deliberate pacing also works to establish the distance Samantha has to travel to reach the house where she expects to do a night of babysitting. He set his film in the 1980s not only as a homage to that decade's horror films, but because it was nearly the last time when a person could be cut off from friends, without recourse to cell phones, Twitter, etc. Once Megan drops her off and drives away, Samantha is on her own in an already dubious situation that seems certain to get worse.
You could argue that West's approach is too low-key to be a true Eighties homage if you identify the decade and the genre with cartoonish killers. This film's head menace is Tom Noonan, who's menacing because of his age, his height, and his history as an actor, but also, paradoxically, of how soft-spoken he is and how fragile he seems. He's professorial in manner and the type of person you could believe is at least some sort of obsessive character. Again, West takes time filming Noonan's scenes with Donahue, letting his creepiness sink in gradually after an already creepy first impression. He has you feeling pretty certain that Samantha is making a terrible mistake staying over, no matter how much money Mr. Ulman offers her, but since he's also established why Samantha needs the money so badly, you don't automatically condemn her as stupid, even if Megan does. If you're watching the film in the first place you have an idea of what's in store for Samantha, but West and Donahue have made her enough of a sympathetic character that you want her to survive the night.
For me The House of the Devil is a big improvement on West's last auteur effort, the sniper thriller Trigger Man. That film struck me as pretty pointless, while the new film is more focused and more effective. To the extent that Trigger Man was a gore showcase, House matches it pretty well with one especially nasty gun-damage scene and plenty of bloodshed during Samantha's showdown with the devil's housemates. Some of the action wasn't as convincing as it could have been (Samantha gets loose from her bonds too easily at one point), and the climax has to stretch to reach the desired evil-wins ending, but overall it's an effective little film with enough heart to make it genuinely horrific. Despite the period music, it struck me as more like a Seventies horror than an Eighties effort -- but that's a good thing as far as I'm concerned.