Corrected entry: In the Two Towers, as the Ents are about to attack Isengard, they have to walk from Fangorn Forest to Isengard. However, in Return of the King, the two are right next to each other. It's not that the Ents have taken root again, because you can see them walking around in the background. It was probably done deliberately, so that Merry and Pippin could see them walking out of the forest, but still a mistake.
Corrected entry: In the scene where Pippin finds Merry under an Orc, look at the dead Mumak in the background. The size is drastically reduced from all the battle scenes. The foot, for example, looks like it could hardly step completely on Merry, a 3'8" Hobbit, let alone entire Rohirrim horses. (02:17:20)
Corrected entry: In the scene where Theoden rides into Dunharrow, he asks "Where are the riders from Snowborn?" the answer is "None have come, my lord"; this is impossible, since Snowborn is a river or stream passing right next to the Rohirrim encampment. What this means is that they cannot come since they would have already been there.
Corrected entry: Eomer shoots an arrow at an Oliphaunt. In the first shot, front view, it is missing nearly its entire right tusk (it shows a bloody stump). In the shot from the rear view, it has an intact right tusk as it falls. (This scene occurs immediately after the one in which Eowyn & Merry charge at, hack at, and down an Oliphaunt).
Corrected entry: In the book The Hobbit, the three trolls that captured the dwarves are turned to stone by being exposed to daylight. The extended DVD of FOTR has a scene which touches on this. However, there are plenty of trolls fighting in the daylight battles in ROTK.
Corrected entry: When Théoden is knocked under his horse by the Witch-King, it's obvious that the Fell Beast is attacking so Théoden is looking down at him, with the horse's legs pointing at the Fell Beast, yet after Éowyn destroys the Witch-King and Théoden passes away, we see a wide-shot of the whole scene. Éowyn's discarded helmet and the remains of the Witch-King are positioned at Théoden's head rather than feet. The attack all took part below Théoden, so how did everything shift to above his
Corrected entry: When Aragorn is releasing the Army of the Dead, in the background flags showing the white tree of Gondor can be seen (the same emblem that Aragorn wears on his armour at the black gate). Problem is, no Gondorian soldiers fought in the fields around Minas Tirith, so where did the flags come from?
Corrected entry: On all the closeups of the Ring in Mount Doom, there are numerous flashes in the chamber that look like lightning flashes, or some other form of "blue" light. There wouldn't be any light of that color in the chamber because it is all fire and lava.
Corrected entry: On the DVD, in the scene where Gandalf is driving the carriage (with Frodo and Bilbo on board), in the zoomed out shot you can see four hobbits riding on ponies. There should only be three. Since Frodo is in the carriage, that would only leave Sam, Merry, and Pippen. These are the only hobbits going along, since they are the only ones at the harbor.