When Moe and Curly escape the room, a fallen chair lands from the top of the door, even though there was no set-up scene involving it.
When Curly unintentionally carries Mrs. Leander into her room, his arms are in a different position than before he picked her up.
When the wolf man bends the bars to escape his cage, two of them immediately spring back up.
Moe's cue to yank Curly into the Leanders' room with a hammer comes too early. In the next shot, when they are in the room, Moe still has the hammer on Curly's nose.
This short is set primarily on the eighth floor of a large hotel. In the room where two women are sleeping, the wolf man enters through their bedroom window. However, the scenery behind him is of a street level residential neighborhood.
The music can still be heard playing when the wolf man takes the trombone away from Curly.
When Curly plays the trombone to "tame" the wolf man, a whole band is heard playing instead of a trombone.
Visible wire on the knife that is thrown at Curly when he brings the trunk into the apartment.