(at around 53 mins) When Amy is stabbed she gets up out of bed. In one shot there is a thick spot of blood on the right shoulder of her night shirt as she gets out of bed. Then, as she stands next to her bed for a few seconds, the blood on her right shoulder is now light and smeary and not thick as was already shown. When she gets into the bathroom there is now no blood on her shoulder.
(at around 33 mins) When Amy is walking through the subway, the multiple earrings that she wears normally on her right ear now appear on her left ear, then back to her right in the next cut.
(at around 22 mins) When Amy grabs the envelope and the box from the "dead" woman in the bathroom, she takes the box from the woman's left hand and puts it in her bag. When the woman "awakens" you see Amy jump away. The scene then cuts to the woman in the bathroom and she is still holding the box in her left hand after it was supposedly removed.
(at around 1h 15 mins) When Amy performs the suicide ritual, the knife repeatedly changes position in her hands between shots.
(at around 1h 19 mins) When Winter is caught up in the chains, the hook in his left cheek disappears in one shot, then returns the next time Winter is on screen.
(at around 39 mins) When Amy unlocks the gate she only unlocks the lock without removing the lock itself and gets right through with a push even though we can see the chains wrapped around it multiple times. After she walks through, we can see that there are now no chains or lock on the gate at all.
(at around 20 mins) When Amy walks into the bathroom containing the "dead" Marla, the actress playing Marla can be seen exhaling (at the base of her ribs).
The shot of the train pulling away is flipped. Just as it almost goes off screen right, we can see a "MA1" sign on the wall just behind it which is reversed.
(at around 25 mins) When Amy is sitting in the hotel room, she takes the box out of her bag, and inspects it; as she is inspecting it, there is a cut scene to her sitting in the distance; in this cut scene, it shows Amy on the telephone, which is also sitting beside her, then it goes back to her staring at the box, just away to open it, then the chains come out of the box and grab her. Also in this scene, there is visibly blood on her mouth and teeth, which disappears in the next shot, after her brush with the chains and Pinhead, she sits back in the chair and the telephone rings, yet the telephone is no longer beside her, but on a ledge at the back of the chair.
(at around 13 mins) Although the paper is based in London, the money in the envelope that Charles gives to Amy is American currency. Likewise, the bribe that Amy gives to the landlord in Romania is also in American currency.