If this sounds like a recurring nightmare, it may be because director David Robert Mitchell based the story on his own bad dreams as a child and the pervading atmosphere that haunted him. The movie has a beautifully eerie 80s ambience, even going so far as making a nod by giving the protagonist famed scream queen Jamie Lee Curtis' name (Jay short for Jaime), and Jay's younger sister has the same as Curtis' sibling. There's a definite feeling of John Carpenter in the phenomenal soundtrack, which thrums with both a throbbing foreboding and synthesized panic. Mitchell uses wide angle shots to full effect to create suspense and disorientation when necessary. There are some spectacular spinning shots and the use of expansive space in some of the scenes is droolworthy. I actually think the use of digital in this movie rather than film adds to the nouveaux-retro ambience -- alluding to a bygone decade while giving us the crisp image of an urgent present.
The young cast of It Follows captures the innocence and unabashed uncertainty of youth that combines with highly self-conscious actions. There's been much speculation as to the metaphorical meaning of the apparition in It Follows. Mitchell himself doesn't think it necessary nor appropriate to pinpoint what it represents. It's fairly easy to label it as a metaphor for STDs, but that's just the surface. There's an idea of coming of age, and the uncertainty of life that looms so large that we're not able to escape it once we leave childhood behind. There's a threshold in the lives of these characters, where adults are peripheral and unable to help in a significant and meaningful way.
It would be false to compare this to Cabin in the Woods as some critics seem bent on doing. It Follows is self-aware, but not to the point that it needs to remind us with clever nudges. What's clever about it is putting teenagers down in a horror situation where they don't have the excuse of blind panic in the moment for their reactions. What happens when it's not a psychopathic killer that's lunging at you and forcing you to scramble up the stairs? What happens when it's a force that can't be contained, can't be halted, and gives you time to dwell on your impending doom?