While Marnie and Splendora are in the royal room, Marnie's eye colour shifts from blue to green across several shots.
Towards the end, when the Cromwell Necklace is destroyed, Ethan's hair shifts from being spiked at the front, to spiked all over, and then lies flat just as he walks towards Marnie.
When Marnie and Dylan step out of the taxi and walk up to the first building, they're not carrying any suitcases; however, in the next scene they're shown with them again.
When Mrs Piper is paying for her groceries in the supermarket, she swipes her card with the magnetic stripe facing upwards, so it does not register. She then proceeds to key in her PIN and authorise the payment.
At the start of the film, when Gwen Piper is speaking to Aggie from inside the soup pot, it may sound as though Aggie is calling her Linda. In reality, she is saying 'Gwenda', a diminutive of Gwendolyn.
