Okay, I went in expecting great things, and it exceeded all those expectations. The film is rich, deep, impeccably-crafted, and extraordinarily effective. Normally, when I read someone's negative reaction to a film, I can see their points, understand where they're coming from even if I don't agree with them, but in the case of It Follows, I read a negative review and all I can think is, "What the hell are you talking about?"
The film is a masterpiece of tone, to start. The languid rhythms of the editing, the long deep-focus shots of slowly approaching horror. Jump scares don't scare me, gore and violence don't shock me, but I respond to dread. It hangs thick over this entire movie like a wool blanket smothering you. Dread is the currency of this film, and it spends freely.
I'm also baffled by comments about the characters behaving unrealistically, or illogically. This is the rare horror film that allows neither the characters nor the audience any special insight into the nature of the threat, beyond what they piece together through their own experience. So yeah, they try things that seem like bad ideas in hindsight, but that's because they, much like us if this were happening in real life, are making this shit up as they go along. They carry out their bad ideas because the alternative is to give up, to sit down and wait it out. And if we learn anything from the opening sequence of the film, that's a much worse idea than anything these characters come up with themselves.
Speaking of the characters themselves, sure, there's not a ton of development to them, besides Jay and to some degree Paul, but so what? Those characters are not the focus of the film; they matter in relation to the protagonist, not in and of themselves. And the social dynamics of that group of characters is so perfectly, relatably drawn. There's never an instant of the "why would these characters be friends with each other?" feeling you get in almost any film featuring a group of friends. These people have complex patterns of relationship and history that can be inferred with the barest minimum of exposition. To me, there were no false notes here.
Then we get to the meat of any good film: theme and metaphor. Upon coming up with the central concept of the film, it would have been the easiest thing in the world for David Robert Mitchell to plaster simplistic moralizing over it. Slasher films have been doing it for decades: you fuck, you die. Thank god he's not that lazy, and has deeper sensibilities than that. Because the themes he finds in the premise are infinitely more compelling. The primary one being: sex complicates relationships.
At its basest level, It Follows is the story of a girl who was unable to escape her home town after high school, and finds her sexual prospects limited by that circumstance. And within those limited prospects, each relationship has a different potential to backfire. There's the guy who's not from her hometown, who represents the exciting world outside her limited perspective, but who turns out, after she's had sex with him, to not be the person she thought he was. There's the guy she had fun with back in high school, who represents the stuck-in-the-small-town loser she herself is afraid of becoming. The stakes seem low enough, because there's no real connection, no deeper emotional commitment, and for a few days, it seems like everything worked out fine. But ultimately, his own cavalier attitude, which made him seem like the safe option in the first place, leads to hurt.
And then, of course, there's Paul. Poor naive Paul. The ultimate case of unbalanced affection. Jay likes the guy. She cares about him. But she doesn't like him and care about him the way that he does her, and this makes choosing him as a sexual option positively toxic. His destruction is inevitable. But Jay reaches the point where she is beaten down too far, and his persistence is too psychologically reassuring, and she fucking does it anyway. The movie mercifully ends before we have to witness the aftermath of this decision, but it's also merciless enough to make it crystal clear that the aftermath is going to happen, likely sooner than later. This is not a rose-colored lens, "Love Conquers All" movie ending. This is real goddamn life and people get hurt when you make poor emotional decisions.
This is such a good movie. This is everything that I look to get out of cinema. It kills me to see people not like it.