This movie is unsettling. To its credit, that is partially due to its commitment to the relentlessly bleak and bloody life of Tasya, a woman whose job is to use a strange machine that lets her inhabit other people's bodies to carry out violent assassinations. The film truly conveys the dread of an alternate universe where such a thing exists. The audience is in a strange position at the edge of the seat waiting to see how this woman and her overlords' missions go, yet also wondering if we should be hoping for their own demise given the immorality of their scheme. It doesn't help that Tasya herself seems perturbed about her own actions.
Unfortunately, the film is also unsettling for a number of negative reasons. Firstly, it is grotesque. It features ridiculously gory violence and pornographic imagery, including a scene where a child is shot and killed and highly explicit sex scenes. These kinds of elements can be appropriate when crafting a film, but the creators of this film are highly egotistical to think that they have the skill to use these elements as anything more than shock value.
Secondly, the actual writing of the film is lazy. It is premised on a fascinating science-fiction concept of using technology to control other people and have them carry out violence for you, but that is the only substance to the film. None of the people in the film seem like living humans; they are just there to either kill or be killed. There is no way to connect with or care about anyone in the film, except when you feel sorry for them being brutalized so viciously or wish they would stop committing such heinous acts. Very few things are justified in the movie. Why, in a world that mostly seems to be just like our own, do they have this incredible ability for one person to take control of another's body? Who exactly is doing this? How would this be worth it, given the monetary, legal, and ethical liabilities? Why would anyone agree to do this? Why does no one notice? Why are the victims left alone so much, without anyone there to help them? This mystifying world is actually just an empty world, like a notepad with only two pages of notes and the rest is blank.
Finally, the movie veers into government-granted film student cheese. While it is stylisticly interesting in some ways, it also features a constant soundtrack of grating royalty-free "creepy" music and features a lot of "eerie" filler footage. At the supposed climax, it devolves to the point of plopping loud, scary sounds onto otherwise laughable scenes with melting masks and spooky scenes flashing by.
Possessor is highly dedicated to some sort of goal to unsettle us. Unfortunately, it just isn't clear what the purpose is, and therefor it is not justified in being so grotesque and unenjoyable. It joins a growing legacy of films which collect grants from multiple countries, go to print, and then get tossed in the rubbish cause no one cares.