Jacob Gehman’s review published on Letterboxd:
I'll be curious to see how I react to Possessor on a rewatch. Coming into it I was expecting more of a horror film than a tech thriller. I mostly transitioned into what Possessor is despite the misplaced expectations, but I think a rewatch might smooth over some of the early stage bumps I experienced.
Even granting that initial disconnect, Possessor is a fierce experience.
I'm going to mark the rest of this review with spoilers because I think if you haven't seen the film yet, talking about specifics—or even larger generalities—will interfere with the way Possessor advances, intentionally pacing its information. Suffice to say, if you like tech thrillers, Possessor is definitely worth the time.
Possessor follows Tasya Vos, an assassin who uses technology to possess the body of someone who has access to the victim. Plug in, imitate, eliminate. It's a career that has consumed her life; she's left her husband and son out of the fear that her lifestyle will put them in danger.
That danger isn't alluded to in concrete terms (little in Possessor is), although the early stages of the film suggest worries that the people who plug in—do the possessing—are always at risk of coming back different. Personality shifts, perhaps, or a sort of merging with the host body. A post-possession test administered by Vos's boss tries to delineate this: A box of items, some that relate to Vos's past, some random. If she I.D.'s the correct things as hers, she's cleared. We see, after Vos's first mission shown in the film, correct identifications, although Vos's boss expresses some worry. The tests aren't revealing anything, but there's an undercurrent to the way Vos has been acting—and the way she completes the mission—that shows red flags.
Possessor is a journey of a person more than it is a goal-driven plot. Exploring this high concept job and how a normal, subdued person like Vos can commit acts of shocking violence while in the guise of someone else. We take this journey with her; even though we don't know the details of who Vos was before, we can still infer how a high-impact job creeps into her psyche. Which may explain why she felt the need to separate from her family; however she's changing, she may not be able to guarantee one day that she won't wake up one day with a bloodied knife in her hands.
It's a fascinating film with a compelling journey that showcases some genuinely interesting ideas. At the same time, there isn't a beginning-to-end narrative here; a journey is only a viable plot when something resolves or is clarified at the end. I don't think Possessor succeeded on that front. An ending is implied, but in a way that feels more like a comma, not a period. Still a worthwhile journey, but that failure keeps Possessor for reaching its potential.