Revealing mistake: Right before Rick grabs the half of the broken dagger, he is starting to stand up, only to be kicked by the Dragon Emperor and slide back about 8 feet. As he starts to stand again, you can see that the background is exactly the same as the first time he tried to stand up - meaning that both moments were taken from the same shot, despite the fact that the background should now be different.
Revealing mistake: When Evie and Jonathan jump out of the truck before it crashes (during the chase scene right after the Emperor is brought back), as Evie lands on the ground you can see the outline of the kneepads she is wearing beneath her stockings. You can also get a brief glimpse of the stunt-woman's face, and she's very obviously not Maria Bello.
Revealing mistake: When Mad Dog sees the Dragon Emperor walking through the snow shortly after Rick and Evie leave, we see him rub some fog off of the window he is looking through, and it is very clear that the fog is computer generated. It doesn't disappear "correctly" as he wipes it away.
Revealing mistake: As the emperor raises his army, you see the holes form into the ground and the armies march. After a close up and the camera pans to get a larger view, watch closely and you can see the army take a totally different formation, caused by a computer generator. (01:19:40)
Suggested correction: The scene is edited using montage-style editing. (Including obvious fades and time-jumps.) It would take far too long to show the scene start-to-finish in real-time. The fact that the formation changes between shots is acceptable within the context of a montage because a montage implies passage of time between edits.
Revealing mistake: Just before the final battle, as the O'Connells are preparing, you see Rick and Evie emerge from behind a rock with guns in hand and cautiously watch over what is happening. In this shot, Evie is holding two pistols, and you can see that one of the pistols (should be on the viewer's right) has a bent barrel, revealing it to be a prop of some sort.
Revealing mistake: When Lin flies down and kicks the evil general into the gears, it's painfully obvious that the actress is on a wire. Her body unnaturally sort of floats as she's performing the kick, then after she's made contact with him, you see her unnaturally move backwards and land on the ground while clutching something invisible (presumably the wire that was painted out) in her hand. When she lands on the ground, it's also clear from her feet not touching the ground "properly" that she's being suspended.
Revealing mistake: When the Emperor attacks the village in the beginning after the assassination attempt, watch closely. During the fourth shot, a soldier hits a villager over the head with something and there's an audible sound... but you can see plain as day that the soldier was nowhere close to actually hitting the villager. He stops a good 3-4" away from actually hitting his head.
Revealing mistake: When the evil general is kicked into the gears and crushed, the second camera angle gives away the fact that the gears are actually nowhere near touching at all, and thus, the general is not actually being crushed. Obviously they wouldn't actually be touching because they wouldn't want to hurt the actor... but they could have picked a better camera angle that didn't give it away.
Revealing mistake: When the Yeti arrive, the second soldier that is attacked is picked up and thrown into a doorway. When he lands, you can very briefly see the snow for a few feet on either side of him "pop up" in the wide shot, revealing he landed on a pad. The camera cuts to a different, closer angle after about 5 or 6 frames, so it can be hard to catch the first time, but if you know where to look, it's very obvious. (Slow motion can help, but is not required).
Revealing mistake: When Rick catches himself in the neck with the fish-hook, if you look closely when Rick pulls on it, it's pretty obvious that it's a prosthetic. Not only is the skin around the hook a lighter shade than the rest of his neck, but the way it stretches and wrinkles is completely unrealistic, giving it away as a small sheet of latex.
