Revealing mistake: After the Witch King destroys Gandalf's staff, the wizard and Pippin fall to the ground in the wideshot. In the next close-up, as Pippin (who is behind Gandalf) raises his right leg while he gets up, the white/black sneaker he wears is briefly visible on Billy Boyd's Hobbit foot. (Extended version). (00:24:10)
Revealing mistake: In the first scene in Edoras (the capital city of Rohan). The first pan over Edoras: You can see that the pan is shown in reverse, with the smoke going into the chimney and the fire at the end is burning backwards. The flags are also fluttering the wrong way, as are Éowyn's hair and clothes. (00:12:10)
Revealing mistake: After Gorbag says, "You touch it, and I'll stick this blade in your gut," Shagrat and Gorbag start to fight. A few shots later there's a close-up of Gorbag who is bald, he's not wearing his hairpiece/wig in this shot, as he's being pushed towards the right of the screen by Shagrat, just before falling into the hole! (02:19:00)
Revealing mistake: In the scene inside Mount Doom after Gollum bites Frodo's finger off and it appears they have both fallen into the lava, Sam looks over the edge of the cliff and sees Frodo hanging on. Just after Sam says, "Take my hand!" as Frodo tries to grab Sam's hand, you can plainly see Frodo's "missing" finger bent in half to give the appearance that it is gone, complete with the blood and gore seen just after the finger was bitten off initially. (02:44:25)
Revealing mistake: When Legolas is climbing up the oliphaunt during the battle of the Pelennor fields, there is a shot of him moving along the oliphaunt's side. During this shot, he pivots a bit on the rope he is holding. When he pivots towards the side, you can see that the arrows in his quiver pass through the skin of the CGI creature.
Revealing mistake: After Théoden orders to reform the line, when the Mûmakil approach, Éowyn and Merry (from his eyes up, actually) are seen in close-up as she shouts during their charge. This is the same close-up of them shown earlier, when the Rohirrim charge at the Orcs, only it's been flipped for this scene. (00:28:35 - 00:32:30)
Revealing mistake: At Minas Tirith, after Frodo wakes up and finally sees Gandalf standing at the center of the footboard, there are three wideshots which face the doorway from the side of the bed. In that second shot, when Gimli stands in the doorway, just as he throws his arms open, a laughing Gandalf's eye contact is not in line with any of the Hobbits. Frodo, Merry and Pippin are huddled together in Frodo's bed, and Gandalf's eyes are actually looking to their sides.
Revealing mistake: At the stairs of Cirith Ungol, after Gollum says, "Come away, Hobbits. We climb. We must climb," there is close-up of Hobbit feet. The next shot as Frodo and Sam climb, is a flipped shot - just note the stew pot on Sam's back, it is on his left side, though he carries it on his right side. Sometimes, what gives away the reversed shots are the Lórien leaf brooches or Sam's pots and pans.
Revealing mistake: Trying to save Faramir, Pippin shouts, "Gandalf!" and in the first shot from behind Pip, he runs towards Gandalf, the Gondorian soldiers run towards the camera and he is perfectly Hobbit sized. However, in the next shot, facing Pippin, he is not only further away than in the previous shot, when he runs towards the camera as the Gondorians run past him, Pippin is now much taller, almost as tall as the soldiers he passes. (02:00:50)
Revealing mistake: When Merry and Pippin are entertaining the men and women of Rohan with their "Green Dragon" song, there is a woman at the right rear corner of the table on which the hobbits are dancing who looks at an empty spot behind Merry at the finale. No doubt the actress was looking at the spot she presumed the hobbit would be "pasted" into during editing, but she's off a few feet. This is further emphasized when she hold out both hands in a "take a look at this" gesture and again indicates the empty space behind Merry. (00:14:15)
Revealing mistake: The two doors of the CG Black Gate continue to open wide, as Aragorn and the others ride away from the approaching Orc army. When Aragorn rides as he shouts, "Sons of Gondor, of Rohan, my brothers....when the age of men comes crashing down," at the top of the screen the 'closed gate' is visible above the shadow. (01:13:00)
Revealing mistake: During the charge of the Rohirrim on the Pelennor fields, there is a close-up of Éomer. His spear is held in his right hand, he tosses it up and amazingly changes his hand position on the spear in mid-air as he rides. Another rider is behind Éomer to his left and as this man rides the spear he holds above his head bobs up and down like rubber, as does the spear behind Éomer's right shoulder. (02:00:30)
Revealing mistake: At Dunharrow, Merry watches as everyone rides off, and in the shot of his back Éowyn's fingertips reach his right shoulder. In the next front close-up, she's still further back, note her fingers behind his head, but he starts to rise off the ground even as her hand is just coming closer. (01:26:05)
Revealing mistake: Though the effort is made to hide Shadowfax's saddle under Gandalf's cloak, bits of it are still visible in some shots as Gandalf rides the horse. For instance, when the wizard rides with Pippin to save Faramir from Denethor, just as they exit the tunnel in front of the Witch King, the brown saddle is seen right behind Gandalf's knee, though his robe is deliberately secured at the bottom to prevent this.
Revealing mistake: In Osgiliath, while the Gondorians battle the Orcs, in quite a few shots it's obvious that the fighting is staged. In one shot in particular a helmeted Orc slams his double blade axe into the chest of a Ranger, yet it's clear that the sharp axe does not leave any mark whatsoever as he falls to the ground. (00:52:00)
Revealing mistake: In Arwen's vision, as the child (which she realized to be her future child with Aragorn) runs past the plants in the wide shot, the area between his knees and ankles become very thin, dark and partially disappear, then reappear while he runs. However when he reaches the steps and stone ground within the same vision, his legs are normal again, as he was filmed on that set, whereas he was 'pasted' among the greenery. His upper body though, remains normal throughout this shot. As soon as he reaches the stone floor, which is the set that he was filmed on, his legs are normal again along with the rest of his body. There should be no differentiation in the appearance and disappearance of part of his legs between the backdrop of greenery or the stone of Minas Tirith within the one vision, but there is. (00:27:05)
Revealing mistake: On the Pelennor fields, the Rohirrim battle the Haradrim on Mûmakil with their bows and arrows. In one particular shot the Rohirrim in the foreground ride towards the right of the screen and the rider at the left lets loose one arrow, then reaches behind him to get another arrow and brings his arm back to the front. However, no arrows are ever visible in his hands. (02:05:20)