Critical response
On the review aggregator website Rotten Tomatoes, 90% of 59 critics' reviews are positive, with an average rating of 7.4/10. The website's consensus reads: "More visually impressive than narratively engaging, Vesper rewards patient viewers with immersive world-building and intelligent ideas." On Metacritic, the film has a weighted average score of 70 out of 100, based on 10 critics, indicating "generally favorable reviews".
Olivier Delcroix, writing for Le Figaro, found the film "the result of a string of carefully thought through choices, a very beautiful immersive movie that resembles a strange sci-fi fable, fascinating and otherworldly." Philippe Guedj of Le Point found "influences from Cronenberg, Giger, Jim Henson or even Miyazaki", with "the movie zigzagging between a Grimm fairytale mood and a hyperreal painting of a medieval future."
Ben Croll of TheWrap deemed the film "something wholly unique—at once modern and timeless, nostalgic for a genre only just created, already pining for images freshly cast up on screen." Robert Daniels, writing for RogerEbert.com, remarked that "you'd think someone like Vesper who's experienced so much tragedy and misfortune would carry at least a twinge of bitterness or some flaw", but wrote that "[t]he major draw of Vesper, however, is the imaginative world building by Buozyte and Samper." Guy Lodge of Variety described it as "a sci-fi film fascinated by earthly survival, not sleek, state-of-the-art spectacle—though it often dazzles just the same", and praised "the sophisticated technical realization of this desperate dystopia...achieved on a budget presumably a fraction of that granted to most franchised Hollywood fantasies". Writing for New Scientist, Davide Abbatescianni labelled it an "exquisite dystopian sci-fi" with "a Brothers Grimm edge" as well as "a good example of what European science fiction has to offer."
Screen Rant rated it a 3 stars out of 5. The header summary stated: "Two elements—the design-driven worldbuilding and Vesper's development—keep viewers engaged, but they have to overcome a few weaknesses to do so."