Absolutely loved the concept. As some of you may know I'm an avid horror movie fan. It takes a lot to actually scare me due to some of the things I've experienced being far scarier. (See 2 blogs back.) That said It Follows put a couple of small shivers up my spine which for me is a definite achievement.
However, that all said, I dislike movies that don't finish properly. Yes there's the whole "it leaves it up to your imagination" thing, but personally when I watch a movie it's because I DON'T want to leave it up to my imagination. And what I can see coming from this pretty decent movie is an It Follows 2 or 3 or 20 all using the same concept which will fast become washed out.
There was also a distinct lack of explanation on what "It" was. Thereagain if there's going to be an It Follows 2 then perhaps that will cover it? I have literally no idea. I know the completely unexplained can be scarier but my curiosity gets the better of me and irritates me.
All in all I would give It Follows 7/10. It was definitely a 10 on original concept, but the couple of niggly things brought it down for me, which is a shame.
Actually enjoyed reviewing that maybe I'll do another soon.