Near the beginning of the film, when the photographer is taking pictures of Melissa and Nikki's corpses, Melissa's eyes are open. But, in the scene where Melissa stabs herself, she dies with her eyes closed.
When Melissa and Nikki go into the bathroom to do there make up they both have their dog collars on, but when they come out and walk in shots they both have it on then it disappears in the next shot.
In the story of the ladies stealing from the old man. Sophie puts his false teeth in but when we see the old man he has a full set of teeth.
Also the floor board she tripped over is flat when she wakes up. All the money Sophie put in the shirt is missing too.
Richard uses a search engine called Ask Eddie to search for The Sick Room. However, a brief closeup of the screen shows text from the Ask Jeeves search engine. (The name Jeeves is especially noticeable.)
Near the beginning of the film, Emily Booth's character visits her friend's apartment. As her friend brings out refreshments you can see what appears to be a camera shoot in on the left side of the frame and then slowly move its way out of the shot.