Revealing mistake: While on the balcony at Minas Tirith, Pippin asks, "Is there any hope, Gandalf, for Frodo and Sam?" and in the next back shot of Gandalf standing beside Pippin, the Mordor 'storm' brews in the CG distance. The dome of a building is directly in front of them, to the right. When the beacon of Minas Morgul rises to the sky, there is another back shot of Gandalf and Pippin. In this shot that building with the dome is gone, though it should be visible! (This has nothing to do with camera angles. Extended Edition.) (00:53:40 - 00:57:25)Super Grover
Revealing mistake: In this shot at Minas Tirith, Gandalf says, "Peregrin Took, my lad, there is a task now to be done," as they walk out from under the archway and pass a particular tall white stone building, on their immediate right, as they continue to walk on. After Gandalf says, "You must not fail me," Pippin runs toward a building and as the camera pans up the very distinct markings on the large stones are identical to the markings on the stone building in the previous shot. Obviously it's the same building used in both shots of different areas. This type of thing occurs numerous times in the film. (01:00:15)Super Grover
Revealing mistake: Faramir and his men retreat towards Minas Tirith, someone shouts, "Take cover, my lord! It's coming!" In this shot Faramir starts to duck from the Nazgul overhead and seen to his left are his men. After Gandalf rides towards them and a Nazgul lifts a horse and its rider, Faramir is ducking again with the same men to his left in the same positions as the earlier shot. Obviously this is the same sequence that was edited to include shots in between. (00:53:55)Super Grover
Revealing mistake: When the Orcs attack Osgiliath, Faramir takes his sword and it appears as if he plunges it into the belly of an Orc. However, he really turns the sword before it hits the Orc and the tip coming out of the back of the Orc is CG. The angle of his hand on the hilt as the blade penetrates and the CG blade in the Orc's back do not line up. (00:46:20)Super Grover
Revealing mistake: In several crowd shots of Minas Tirith during Faramir's suicide charge (particularly the one featuring Irolas), the top of the set is visible. Buildings stop unnaturally, and the sky is visible where the other walls of the city and the mountain range behind it would have blocked it.
Revealing mistake: At Minas Tirith, Grond breaks through the door, then Trolls and Orcs attack. After Gandalf yells, "Volley! Fire!" there is a shot of Orcs, one of which is somewhat bald at the bottom of the screen in the foreground, who run towards the right of the screen. Then other shots including Gandalf slaying a Troll. The last shot of this scene is the same shot of the Orcs running to the right of the screen. (01:48:15)Super Grover
Revealing mistake: When everyone is sleeping on the floor in the Golden Hall in Edoras, Gimli is seen lying on the floor next to a man. They're the same length - you can tell my the position of their feet under the blankets. Gimli is supposed to be about 4 feet or so, whereas a man is supposed to be around 5-and-a-half to 6 feet.
Revealing mistake: During the charge of Pelennor fields, when the Rohirrim are fired upon and when they clash with the Orcs, in many shots either the Rohirrim, horses' bodies or Orcs partially disappear and may reappear within the melee. For example, when the riders are fired upon the real horses run right through some fallen CG horses and riders and in another shot two Orcs' arms disappear as horses ride by. (02:00:10)Super Grover
Revealing mistake: On the ledge by the stairs of Cirith Ungol, Sam tends to Frodo, who has collapsed after intervening in Sam's violent beating of Gollum. As Sam's offer to, "Carry it for a while - share the load," echoes in voice-over, there's a close shot of Frodo's face, wherein contact lenses are visible (in the right eye in particular). They are also noticeable in the following close shot (after Sam tells Gollum to "Go away. Get out of here") as Frodo says, "No, Sam... it's you." (Elijah Wood did not wear tinted lenses, only corrective lenses.)
Revealing mistake: At Edoras, Merry and Pippin sing the song about the Green Dragon while dancing on the table. When Merry kicks Gamling's mug of ale off the table, Merry's foot gets thinner and partially disappears in this shot as does Pippin's foot in the next shot as he kicks up. (00:13:55)Super Grover