Let the Right One In is a cute movie in relation to the horror genre. Given that it’s pretty gory in itself, that is beside the point that the movie drives home. The central monster that the movie plays with is the vampire, a monster of charisma, power and tremendous affect.
The vampire, unlike the cheapened iterations of it in recent trends in films, is a monster characterized by its appetite for human blood. The horror on a natural level being that the vampire presents a clear opposition the cultivated lifestyle we have where we are the modern-day top predators. This threat to the dynamics of powers to the natural order of things is further deepened by the fact that the vampire presents itself as further empowered version of ourselves (i.e. looking human). But beyond that, the movie also classically plays on much of the mythological baggage that the vampire operates on like the fact that they can only be invited into a home and not come inside without consequence, or that they burn in the light. The movie titular basis is the former of those two, and an interesting aspect to play upon in the movie.
I don’t think I’ve ever come across any kind of monster that was so polite as to need to be invited in before it can disturb your life in your own abode. The act of letting in a vampire, of letting in a horror, is unthinkable even if you knew they were one by common sense. It’s strange how the vampire is framed as something that respects or rather is bound by certain rules of conduct. But in a way, the issue of space and the vampire is kind of like the say way that the realization of horror penetrates our understanding. We only understand it the moment it has entered our realm of reference and understanding but the moment it has done so, the moment it takes that step inside, which we let it, it has power over us.
The movie presents a skew on that though. The way Oskar lets Eli into his house and even into his life; he subverts that and internalizes the horror into his life. Oskar leads a life where he is almost powerless. The disturbance that Eli brings his life is that it opened him to the realization of his weakness and his inadequacy. It’s interesting that to some degree that Eli is a sort of parallel, not unlike a mirror, by pointing out the exact things he lacks. The element of horror, once inside our space of the sacred and is internalized, reveals to us our own unconscious desires. The dynamic of coexistence with the horrible is one marked by reflection on, among other things, knowing and understanding that we are that powerless and capable of being so in the face of greater natural forces. As a means of fortifying ourselves against horrors there is a need to learn to accept them as well, almost like a means of vaccination against greater sources of horror.