Anachronisms: The movie is supposed to take place in 1958, as the opening scenes state. When the children leave the house in the beginning of the movie, one of the cars accompanying the buses full of children is clearly a white Peugeot 404. Peugeot introduced this model in 1960, and made it available to the public a year later.
Crew or equipment visible: In the scene where Anna breaks the glass in the bathroom and tries to get in, a man with a camera can be seen in the remaining mirror.
Continuity: When Anna and Judith are trying to escape from Helenka, Anna wraps only her right hand in paper to break the mirror, seconds later both of her hands have the protection to avoid cutting herself.