Colonel Mustard: Wadsworth, am I right in thinking that there is nobody else in this house?
Wadsworth: Um, no.
Colonel Mustard: Then there is somebody else in the house?
Wadsworth: No, sorry. I said no meaning yes.
Colonel Mustard: No meaning yes? Look, I want a straight answer, is there someone else or isn't there, yes or no?
Colonel Mustard: No, there is? Or no, there isn't?
When Mrs. Peacock turns on the cellar lights, a piece of lighting equipment is visible to the left of the screen.
Not a mistake, just a neat little fact. When the film was being shown at cinemas, only one ending was shown. Different venues had different endings.