Errors made by characters (possibly deliberate errors by the filmmakers): Pilar describes the old cine film that Laura views as 8mm, but when we see the projector, the film is actually 16mm.
Continuity: In the scene where Laura is watching the old films, when we see one of the shots of Tomas, his eye hole is on the wrong side. In the next shot, it is on the right side again.
Factual errors: In the film, we see the lighthouse shining directly on the orphanage. In reality, coastal lighthouses are shielded so their light does not shine on land.
Continuity: During the séance, as Aurora regresses into a trance, her arms slip off the arms of the chair on which she is sitting. The next shot of her, looking from the other direction, shows her arms still resting on the chair again.
Revealing mistakes: After Laura is in the shed outside the house and she finds Benigna with a shovel hiding, and after Laura then tells Carlos to come down and check again with her, Carlos' torch shines onto the camera several times, and the reflection of the camera and the torch is in the background on the window.