Don't be fooled by the marketing, Lamb is not your typical horror flick. I'd put it down as a dark fantasy with minor mystery and horror elements, but clearly that would make it harder to sell the film. A24 fans probably won't mind, the rest should probably brace themselves for disappointment, unless they're willing to take the film as it is.
Maria and Ingvar mourn the loss of their child, when mother nature appears to be lending them a little hand. On their farm a rather special lamb is born, which the couple takes as their own. The lamb brings them happiness, but they'll soon find that the lamb wasn't really meant for them to raise.
Lamb's a pretty typical A24 production. A moody soundtrack, long takes, silent characters, an oddball concept. Director Jóhannsson does well, Rapace and Guðnason put in nice performances, there's just a bit too much filler, and the audiovisual styling isn't quite thorough enough. A slightly more genre-driven approach might've pushed it to be a true masterpiece, as it stands, it's still a pretty intriguing film.