Continuity mistake: Lisle stabs the dagger on Madeleine's finger making her bleed, but in the next angle blood has disappeared from the dagger.
Continuity mistake: At the book signing Helen kisses Madeline on the cheek and leaves a bright red lipstick mark. She appears to kiss her quite close to the ear but in the next shot, the lipstick mark is more in the center of her cheek.
Revealing mistake: When Madeline is at Lisle's place the first time, she has to sit on a couch, next to a young man. Lisle tells him to make room for Madeline. He stands up and you can see a transmitter on his back attached to his pants.
Suggested correction: This is a security transmitter for the house.
Visible crew/equipment: During the scene when Meryl Streep takes the option, if you pay attention to the effects in the vial you see the top part of a man flash in and out as the lightning effect is happening.
Continuity mistake: Before Ernest lets go of the essence, the way he holds the bottle changes between the back and front shots.
Continuity mistake: When Helen is shot in the tummy, the position of the lilies on the pond keeps changing between shots.
Continuity mistake: After Madeline falls downs the stairs, her hair is messily over her face, but in the next angle it is neatly brushed. Also the position of her hand has changed.
Continuity mistake: In the dressing room at the theatre, Madeline kisses Helen hello and leaves lipstick smear on her cheek. When the angle changes it's next to her jaw.