The reviews lean mixed rather than hostile, with most critics finding more to admire in the performance than in the film around it. Nearly every notice singles out Alison Brie, who plays Sarah with a vulnerability and earnestness the critics describe as compelling and sympathetic even when the story loses its footing. There is agreement, too, that the film’s treatment of mental illness is compassionate and non-judgemental, and that it is more serious than its oddball surface first suggests.
The reservations gather around the script, and specifically its drift into the extraterrestrial. The Guardian argues that the supernatural turn undermines the portrait of mental illness, while /Film finds the film at its best when elusive and weaker once the third act starts explaining itself. The AV Club takes the opposite line, calling the ambiguity muddled. The spread is fairly wide, from Variety’s warm festival notice, which finds the film moving and challenging, down to two stars from The Guardian.