This is the second film of 2011 to play on themes of serious privacy violations following the predictable machinations of The Resident. What that Hammer Films production got wrong, Sleep Tight does right, keeping you engaged with the stalker and not the prey, in this instance, and exploring malicious avenues its English-language predecessor shied away from.
Much of Sleep Tight's potency comes from Cesar, the concierge of a quaint tenement. He's a creep, the walking definition of the phrase "misery loves company." A balding one at that with intense, Muppet-like eyebrows that can either charm you or put you on the defense. And Balaguero loves to play with this imbalance because each one of the residents Cesar serves sees him in a different light, whether it's the elderly woman upstairs who trusts him to check in on her dogs or the little girl that knows Cesar is up to no good and blackmails him on a regular basis for money and an adult film. Then there is Clara, the object of Cesar's desire.
Clara is where things get really screwed up.
Unbeknown to this young, gorgeous, energetic woman, Cesar has formed an unhealthy obsession with her. He has fabricated an imaginary relationship with Clara that, through his own means, carries no physical restrictions. To her, he is the considerate concierge there to greet her each morning as she rushes out to work. To him, she's something to sate his unhappiness. But the impact of the film doesn't come from the methodical things Cesar does to Clara on a nightly basis, it is the reason he does it and Sleep Tight excels wonderfully because of Cesar's impetus. It's rooted emotionally in something deeper than the usual stalker film fare and is incredibly destructive. Yet, you won't find out just how nasty it gets until Sleep Tight's final minutes.
Until that point, Sleep Tight is a tightly-wound, terrific character examination, with a series of unnerving moments, that doesn't feel the need to explain every aspect of Cesar's life. We know he lives in a basement-level apartment of the tenement. He visits his mother on a regular basis, telling her everything he has been up to as she whimpers from her hospital bed (honestly, I grew suspect of whether it was even his mother or not). His boss is consistently browbeating him. And there's something very OCD about Cesar's nature, from the way he wears his concierge coat to how he neatly arranges a series of bottles to his "nightly activities." It's the small details that hammer home who this guy is, and it's enough. Furthermore, it creates an uncomfortable distance between the viewer and Cesar. One is not allowed to get too close to him, but they're absorbed by his actions nonetheless.
Balaguero does a good job of keeping the tension palpable. Cesar faces threats from all sides. Be it the aforementioned little girl, his boss (losing his job means losing Clara), or the police, who are investigating Clara's complaints of inappropriate letters and text messages. But Balaguero's crowning achievement comes when Cesar finds himself in a predicament at Clara's apartment. The viewer naturally wants to see him caught...but also wants to see how he escapes the situation as well. The scene is masterfully played and this is where we see Cesar actor Luis Tosar - who is excellent in the film throughout - at his most vulnerable.
For all of the dread Sleep Tight evokes, it's also a film pulsing with loneliness demonstrated by not just Cesar but Clara and the other residents as well. You almost wish Balaguero allowed the emotionally bereft Cesar to follow through with his suicidal intentions to spare himself any further gloom and spare the viewer the rather haunting gut-punch of a conclusion Sleep Tight ends on. But that would be too easy of an exit for Cesar, furthermore, the audience. There are no easy outs for anyone in this film. Everyone is affected by Cesar's actions. Balaguero, most of all; unlike the others, though, he comes out on top with an unsettling slice of Hitchcockian storytelling that comes very much recommended.