This is my jam right here.
The scariest part of a horror film is never the part where the parents tell the teenagers about how they killed the child murderer, or the occult expert tells the family that there's a ghost in the house or the scientist says that they made the bunnies giant and violent on accident. Fear comes from the unknown, from sharing the characters you're watching's lack of control, and the more it is understood what is happening and why, the less tension an audience feels. The brilliance of It Follows lies in it giving you the most simple details early on, never getting into the hows and whys. Young girl Jay sleeps with a boy, and just when she feels at her most safe and free, he knocks her out, ties her up and explains that something is going to follow her. Somebody gave it to him through sex and he's passed it on to her. No one else can see it, it can look like a stranger or someone she knows. And wherever she goes, it's somewhere, walking straight for her. All she can do is pass it on to someone else. And obviously, if it catches her, that's bad. That's it. And away we go.
It's a refreshingly different take on horror conventions for a number of reasons. It takes the usual horror trope of "teenager+sex=death" and puts a more interesting spin on it, rather than going through a checklist of teenagers to see brutalised only one person is ever in danger at any given time, meaning it's actually worth getting invested in what happens to them. Jay is not a 'scream queen', she's a traumatised person. Since she as our-point-of-view character is pretty much constantly tense/afraid, it helps to put the audience in the same state of mind. Instead of jump scares, a sense of dread hangs over the film, no background extra can be trusted, and the highly skilled widescreen visuals from director David Robert Mitchell make it feel like we're always a moment away from panning to it following, or noticing it following in the background.
It is strong directing from Mitchell, that calls to mind the voyeuristic feel of Halloween and like another film that with a Halloween influence, The Guest (which also shares a female lead with this film in Maika Monroe), this film has a great synth-soundtrack that John Carpenter would appreciate. Composed by Disasterpiece, the music would be good enough to listen to on its own, but works well with what happens on screen, so it's immersive rather than distracting. It is difficult for horror films to maintain the balance of telling a story while keeping enough in the dark to remain sufficiently scary, but the simple approach taken by It Follows goes a long way. It prioritises getting into the heads of its viewers rather than shocking them with gore or boring them with lore and has a lot of interesting subtext about the threat of adulthood and sexual fears (while sidestepping most of the tiresome horror cliches about sex). It Follows is one of the more interesting and original horror films of recent times. Definitely check it out if you get the chance.