Factual error: The movie takes place in New York City, yet a sign on the ice cream store where the mother works says "Take Away." I know they call it "take away" in Britain and Ireland, but in New York it is called "take out." The movie was filmed in New York and Ireland, so that shot was probably filmed in Ireland.
Continuity mistake: When the pregnant Sarah watches the girls trick-or-treating Mateo there's a shot of her belly where she looks like she's almost due, but in later scenes it's much smaller, especially when she tries to keep Johnny from leaving the apartment and holds her hand against her absolutely flat belly.
Continuity mistake: In the scene where Johnny wins the E.T. doll the onlookers keep moving between shots. First Sarah moves from the counter behind her daughters, and later the crowd are either standing still and staring at Johnny or moving and talking to each other in alternating shots.