Revealing mistake: After Lansbury makes her clothes start to move, her nightgown attacks someone and you can notice the strings that make the gown move.
Revealing mistake: When the professor is trying to find the gremlin, he is in the room with the movie playing. The projector that is playing the movie is actually moving backwards. (00:44:35 - 00:47:35)
Revealing mistake: When Ash shoots Cheryl through the door in the head, you can clearly see the hose (not an artery) that's squirting out the blood. (01:16:14)
Revealing mistake: Whenever Rudolph is walking you can see the tracks he makes before he even puts his feet down.
Revealing mistake: The stepmother's arm disappears for a split second when she tells her daughters that there is still a chance for them to become the princess.
Revealing mistake: In the final scene, Superman is returning the White House's flag to its rightful place, flying over the fountain on the lawn...which is frozen solid in place. Obviously a photo backdrop.
Revealing mistake: When we first see Max, his paws are leaning on a balustrade and become transparent. Though it may seem like it's an optical effect because they're in the shadows, the next angle shows them fully lit and opaque.
Revealing mistake: When the old couple who give Wolverine clothes are first driving towards their house, there is an aerial shot of them driving over a bridge. This is supposed to be set in Canada (drive on the right) but it was filmed in New Zealand (drive on the left). They are driving on the right but the arrow on the road is on the left side.
Revealing mistake: In many scenes, particularly the dance scene in the bar, Michael's wings disappear and/or reappear. If you look closely throughout the movie, his wings are often completely gone.
Revealing mistake: In one scene, when Jack is in the dungeon talking to the fairy, you can clearly see that the "fairy" is nothing more than a light on a thin piece of wire. The wire can be seen quite clearly for two shots.
Revealing mistake: Any time when the two girls are in hell's corridors and running around, you see these corridors as stone walls, yet whenever they back up against one of these walls, you can clearly see they are merely rubber sheeting overlayed on a framework as the rubber sheeting bends and contracts very clearly.
Revealing mistake: When Thunderbird 3 lands in London, the jets do not burn the grass they land on.
Revealing mistake: In the scene when Christine smashed repeatedly into the silver Camaro at the gas station, there is no motor in the Camaro. The hood of the Camaro gets knocked off the hinges and is twisted sideways on the car. As Christine is in reverse and dragging the Camaro along you can see down through the hood that the engine compartment is empty. Minus a transmission also, I believe. (01:15:30)
Revealing mistake: When Shrek and Donkey are sitting by the fire and looking at the stars, when Donkey asks Shrek about "our swamp" and Shrek says "We?" When Shrek blinks, his right eyeball is slicing through his upper lid. (00:46:30)
Revealing mistake: When Gary and Wyatt come home and see Chet turned into a pile of poo, Chet shoots his tongue from his mouth and catches a fly. Look closely, the tongue flies completely out of his mouth and is attached to a metal spring. (01:24:55)
Revealing mistake: When the girls are on Aslan's back, you can tell that there is a flat screen behind them.
Revealing mistake: The 'bear trap' clearly has no spikes in it, so how could it have wounded Nathan. This is ever so clear when Tori prises the bear trap open to get his leg out, and it snaps back. (00:52:00)
Revealing mistake: In the park after the bad guys have been defeated and everyone starts returning to the museum, watch the T-Rex closely. In the overhead shot, he seemingly "floats" right through the branches of the trees which he normally would be moving. (01:34:50)
Revealing mistake: Near the end, right before Nita goes after Kenai, she takes off her dress. If you look closely, when she takes it off, her necklace and earrings come off with the dress as if they were a part of the dress. Also, her hair is tied back when she's wearing the dress. But when she takes it off, her hair is loose and flowing.
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.