Continuity mistake: Right at the end, the insurance man gives Charlotte Jewel Mayhew's letter and in the next shot of him, his hands are empty. But in the following shot he's holding the letter again.
Continuity mistake: When Charlotte shoots Drew, her hair is in plaits that are on top of her head, but as time progresses so does her hair. When they are disposing of the body, her hair is down; and when she enters the house, it is completely down and brushed out.
Continuity mistake: Near the end, Velma wants to take Charlotte away from Miriam and Drew; Velma handles the needle and syringe on the bedside table and puts them at the back, but when Miriam comes back the needle and syringe are back in their original spot.