Revealing mistake: Just after Harry attacks Snape at the Shrieking Shack, he insists on knowing about Peter Pettigrew. In the next shot, as Lupin says, "He was at school with us. We thought he was our friend," there are wedges under the wheels of the piano, however, in the following shots they're gone. (01:34:10)
Revealing mistake: When Violet and Klaus make the tent inside their bedroom in Count Olaf's house, they set up the light with the faces of their parents on it in front of it. Except when it shows the shadow of the object outside the tent, the edge of the picture frame isn't showing when it should. (00:21:40)
Revealing mistake: When Thunderbird 3 lands in London, the jets do not burn the grass they land on.
Revealing mistake: In the scene in the alley behind the museum where Hellboy first encounters Rasputin, Sammael has its tongue wrapped around Hellboy's arm. When Myers enters and shoots at Sammael, look closely at Myers' hands. Not only does the gun fire without him pulling the trigger, but the gun does not even recoil.
Revealing mistake: When Jenna is in her bedroom with her mom, as she points to the pictures in the article in Poise magazine, "30, Flirty and Thriving," it is blatantly apparent that it's not Jenna's 13 yr old hand in the close-up, but a much older body double. (00:05:25)
Revealing mistake: When Velma is running from the two one eyed skeletons she goes into what looks like a warehouse and the floor is all wet and in some places there are puddles. When the skeletons come they step into a puddle but the water doesn't even splash or ripple. (01:11:20)
Revealing mistake: When firing the crossbow, Van Helsing runs out of arrows, but the bow's canister is completely full of arrows. In the same shot the canister spins once and they all disappear. (00:25:55)
Revealing mistake: In the scene where Evan wakes up and notices that he has no arms, right when you see the stubs you can see a faint shadow moving next to his head and moving on the headboard. This shadow is the shadow of his hand before it was digitally removed. (00:29:15)
Revealing mistake: During the wedding scene, while the narrator is talking, you can see the string that will pull the left table apart. As said in the commentary, the filmmakers weren't going for the idea of people pulling the tables apart, but rather some other force parting them. (01:27:40)
Revealing mistake: When Jin is fighting in the prison, he kicks two guards into the walls of the stone hall. The one on the right of the screen hits the stone wall making it shake and a block move.
Revealing mistake: You can see Hero Boy putting the ticket in his pocket after getting it punched the second time, before finding his seat on the return journey. However, the ticket slowly evaporates in the air as he is about to put it into the pocket. His hand thus enters the pocket ticket-less.
Revealing mistake: Glenn Close's fillings and dental work are visible in a closeup when she laughs loudly during the new home inspection.
Revealing mistake: At the start of the movie, when the axe gang leader is finishing off the now-one-legged man, you can see in his shadow that he's not hitting the man. Also, if he did hit, you should think that he'd have to pull out the axe blade again, but again in the shadow's arm movement, you see him move his arm in a circular movement, not hitting the victim.
Revealing mistake: In the Arena Challenge scene, the statue of Toa Lhikan falls on the herd of Vahki and part of the statue's mask is going through the ground. (00:22:30)