Time Out says
You might call it an emergent fiction on two grounds: Cuarón had shot a year’s worth of black-and-white stills before he reformulated the drama and re-called the principals to record voiceovers. Equally, the demands this makes on the audience require a gradual, forensic engagement with what they are seeing and hearing. It’s a tribute to Cuarón’s control over his material, however, that the major enjoyment of the film comes not from the experiment but its gentle meditations on belonging, loneliness, family, love and the nature of cultural, sexual and emotional boundaries. In addition, curiously, it’s beautifully acted.