After waking up to find María and Pétur missing, Ingvar takes Ada to fix the broken tractor left halfway to the lake, but the attempt is unsuccessful.

In February 2019, Noomi Rapace and Hilmir Snær Guðnason had joined the cast of the film, with Valdimar Jóhannsson directing from a screenplay he wrote alongside Sjón.

The website's consensus reads: "Darkly imaginative and brought to life by a pair of striking central performances, Lamb shears expectations with its singularly wooly chills.

[20] David Fear of Rolling Stone described the film as "the odd, unsettling, soon-to-be-your-cult-movie-of-choice straight outta Iceland", and wrote: "It's the sweetest, most touching waking nightmare you've ever experienced.

"[21] Jeannette Catsoulis of The New York Times called the film an "atmospheric debut feature", and added that it "plays like a folk tale and thrums like a horror movie."

[22] Michael O'Sullivan of The Washington Post also described the film as a "haunting, atmospheric feature debut", and wrote: "Johannsson has a way of imbuing everything — animate and inanimate, even an empty doorway — with a kind of living, breathing spirit."

[23] Katie Walsh of the Los Angeles Times wrote, "Ominous mountains look down upon the pastoral arena where this fantastical yet meditative rural drama plays out; it's a modern folk tale about the strange realities of life and death that such a closeness to nature affords.

"[26] Richard Brody of The New Yorker was more critical of the film, saying that it "preens and strains to be admired even as it reduces its characters to pieces on a game board and its actors to puppets.

"[27] Barry Hertz of The Globe and Mail criticized the film's ending as being "like a parody of an A24 horror movie", and wrote, "I won't make the obvious joke and say it's baaad.

"[28] Alison Willmore of Vulture wrote, "By the time the final act rolls around, Lamb approaches the idea that there's a price that must be paid with a shrugging diffidence rather than impending doom.