Directed by Jaume Balagueró (Fragile, Rec 1, 2 n 4). The movie is full of tension and claustrophobic with a wonderful finale. It is not the easiest watch at times. The tension is high and the music score by Lucas Vidal (The raven, Fast n the furious 6, The quiet ones) follows the plot nicely. The first scene n the finale fits perfectly like a jigsaw. Very good twist. Non predictable movie. Good acting by the lead actor with perfect direction n awesome screenplay. At times, as a viewer, I felt as if I was also residing in the same building. Such was the impact of the screenplay n acting. Nice screenplay by Alberto Marini. The movie is a dark psychological thriller. The lead actor Luis Tosar (Cell 211, Miami vice, A night in old Mexico) is as odd and scary as Anthony Perkins was in Psycho.