Continuity mistake: When Rennie gets up and walks over to the closet, you can see some items on the side, such as a decorated silk cloth, a bag etc. When Jason then looks through the porthole into Rennie's room, the position of all the items are different. (00:21:35)
Continuity mistake: When Ellie falls from the tree after the rope from the tyre breaks, Louis runs with his wife to see how she is. Louis is wearing a plain white crewneck T-shirt with the sleeves rolled up. When Rachael yells "Gage!", you now see Louis wearing a striped white unbuttoned collared shirt and sunglasses. When Louis is running for Gage, he's back to his plain white T-shirt with the sleeves rolled up. (00:05:40)
Visible crew/equipment: When Horace Pinker pushes the lady in the park, you can see a hand waiting to catch her as she falls back. The hand is visible in the bottom right corner of the screen. (01:00:50)
Continuity mistake: When Tim gets stabbed, the killer's silhouette shows that he's holding his knife overhand. When he stabs Tim, he's holding the knife underhand.
Continuity mistake: When Redferne finds the page of the Grand Grimoire, he is holding it with his right hand. In the next shot, he is holding it with his left hand. (00:52:17)
Continuity mistake: When Fuller falls to his death, the mannequin used as his stand-in gets decapitated on its way down. It even makes a loud noise. When Fuller lands, however, his head is still on his shoulders.