In one of the camera cuts at the dinner table, young Marie is looking at her grandfather when he says "...give it back to Marie," but when the shot changes to another camera, she is looking away from him.
When the killer enters the secret room with Marie, they descend the stairs down the trapdoor, and her shoes have changed from high heels to flat-heeled saddle shoes.
Some character names in the credits don't match up with names spoken in the movie. Speed McGuiness is listed as Speed Dugan, and Marjory Thornton is listed as Marjory Morgan. Adam Thornton's last name is also listed as Morgan.
When the killer grabs Marie from behind and drags her into the secret room, the wall quivers as she bumps into it, revealing that it's only a stage flat.
It's never said who raises young Marie. Surrounded by aunts, uncles, cousins, a grandfather, and the grandfather's lawyer, she and her brother are supposedly orphans, although this is never said. Why the grandfather favors his granddaughter over his grandson is also a mystery. In that he's soon to die, it's curious who becomes her guardian over the next 13 years (since it's a good guess her grandfather has been watching out for her and won't be around to protect her).