The monster in "It Follows" is not a zombie. We never learn what it is exactly, but we are clued into the simple rules that it abides by. Our chief protagonist is Jay (Maika Monroe), a college student who attracts the attention of the monster after sleeping with Hugh (Jake Weary). He explains that she can only be free of it's attentions if she sleeps with someone else and passes along the curse like a supernatural STD. If she doesn't, the monster will stalk and kill her, then resume stalking Hugh. Jay doesn't believe him, even when he shows her the monster, who first appears in the form a naked woman, but can change its appearance to look like anyone. However, she eventually has to acknowledge that she is being followed, and enlists the help of her sister Kelly (Lili Sepe), neighbor Greg (Daniel Zovatto), and friends Paul (Keir Gilchrist) and Yara (Olivia Luccardi).
I love horror movies that use the simplest elements to evoke dread. Here, the unease of being watched and being followed are slowly built up, and built up, to the point of absolute panic and terror. The scenes of violence we see aren't nearly as chilling as the ones that simply show people walking - forcing the audience to guess whether they're looking at the approaching monster or just another passerby. Viewers are often invited to search empty frames for hints of movement, to scan crowds for suspicious figures. There are a few scenes that employ gruesome special effects and slasher-style action, but the majority of the film conjures up terrific tension from our heroes simply being followed or anticipating being followed. And I haven't seen a horror film in a long time that fundamentally understands the value of not showing something onscreen.
The primary actors aren't all that memorable, but it makes all the difference in the world that they're working off a good script and not playing your typical horror movie characters. They get us to care about them. They're not stupid or ignorant. They talk to each other when they have problems, and they behave exactly like you'd expect a group of young adult friends who have known each other for years to behave. I fully expected this movie to feature multiple instances of sexual assaults and sexual coercion, but it's not, because Jay and her friends simply aren't the kind of people who would do that. There is instead a love story that unfolds as the movie goes on, but it's a restrained one, complicated and constrained by the horror.
Many have pointed out that "It Follows" can be treated as a metaphor for sexual morality. Hugh fails to disclose the danger that he's putting Jay in before sleeping with her. Jay's choice in partners is influenced by her desire to stay safe. Everyone's first instinct is to run away from the invisible monster, which often appears in the forms of naked or partially unclothed people. The movie is far too busy orchestrating its excellent thrills and chills to address any of this explicitly, but the ideas are there, and provide excellent food for thought. Even better, there are many different conclusions you can draw from how the film plays out.
I don't count myself as much of a horror fan because I'm put off by the genre's more typical excesses. Most mainstream horror ends up disgusting me instead of properly terrifying me. I like horror films like "It Follows" though. And it did get to me. After my viewing, I found myself second-guessing whether I was alone or not, and whether someone might be watching me or not. The hypervigilance the movie demanded took a while to fade. But the memory of it won't go so quickly.