Hollowface is a demon, an apparition, a nightmare, a spirit, a hallucination, a phantom. He has no face, hence his nickname. He torments people in Spain and also England, but only a grand total of, like, three victims cumulatively. He doesn't much bother anyone in France or Germany. Also, he cares nothing for Switzerland, Finland, Belgium or any of the far northern Eurozones. He won't come when you call him, unlike old reliables Candyman or Beetlejuice. He barely does anything to you once he gets there except hide in your closet or wave a little ooga-booga in your face. Save for haunting Clive Owen, he can't even be bothered to pick on anyone his own size, hoarding all his other scare-power to use on two little kids. So aside from an ability to annoy his targets bilingually, Hollowface is pretty lazy.
That's not to say that this movie is lazy. It's full of little tricks and parallel occurrences and mirrored circumstances, deep psychological and geographical connections (some of which don't amount to anything that makes sense, but whatever), secret boxes in secret holes in secret trees in secret gardens of the mind and, most importantly, a valiant attempt to bubble up an aura of spooky-scary. It fails at that last bit, but you can't say the filmmakers didn't try.
The story goes that Hollowface is haunting a young boy (Izan Corchero) in Spain and also inflicting himself on a young British girl (Ella Purnell) and her construction worker father (Clive Owen). Mom Carice Van Houten thinks it's all a dream, that Hollowface is imaginary, and she brings in the child psychologist to prove it, eventually barring Owen from seeing their daughter. And all of this would be compelling to witness if anyone on screen ever seemed to be in actual danger. Obviously, there's a connection between these three hauntings and, like any dutifully boring movie mindgame will do, eventually everything gets carefully spelled out so you can go home satisfied that you just watched nothing of importance. It would take a real, live Freddy Krueger to make any of this bad dream a genuine threat. But Hollowface is no Freddy Krueger.
So the net effect is like what happens on Halloween when a teenager who's too old and much too tall to be out trick-or-treating knocks on your door wearing a painstakingly constructed but zero-scare-factor hobo costume. He spent a lot of time on the smudged clothes and blacked-out teeth, but in the end he knows better and he knows you know better. Then it turns into a staring contest that nobody enjoys.