It Follows is a bit different from most horror movies, it doesn't feel dark, it's not gory, it isn't extremely cheesy, it doesn't rely on boobs to sell the movie. Don't worry, though, there IS boobs in this movie.
The idea about this movie is that there's something following you, you don't know what it is, you don't even know how it really looks like, because it's always looking like different people. This monster does not give you jump scares, it does not scream, it does not possess things, it doesn't even run. It follows. Slowly. Yes, you can run away, pretty much everything can run faster than that thing, but you can't kill it. And it doesn't stop following you. You may be in another country, or even continent, but be sure to know that somewhere, somehow, that creature is walking in your direction, and eventually, be it in 5 hours, 5 days or even 5 decades, it will reach you and get you.

Unless you pass it on.