Corrected entry: In every shot of Minas Tirith, a city which faces east, with mountains behind it to the west, the sun is shining onto the City from the north. Now this is possible, in very early morning and evening, from May to early August in the Northern Hemisphere...but not at noon-time, and NOT in March (the Ring is destroyed just after equinox, March 25th). We know Middle-earth is Northern Hemisphere since the warmer lands are further south (and Tolkien states in the book that it lay approximately where Northwest Europe is now). In winter, the sun moves southerly and low in the sky. But this was filmed in New Zealand, where winter sunlight comes from the north, not the south, hence so does the sunlight at Minas Tirith in the movie. There's the reason, but still a mistake.
Corrected entry: When Frodo is in the Tower of Cirith Ungol, his shirt is off and you can see a round, burn-like mark; presumably where he was stung by Shelob. The mark is, however, in the area that would have been covered by his mithril shirt. Even if Shelob did pierce the shirt (which would be odd, since it survived that troll-thrust in "Fellowship"), where is the hole when the Mouth of Sauron shows it to Gandalf?
Corrected entry: How in the world did Sam rip the ring off Frodo even though he was covered with webs, pick up his sword that was far away from him, find a hiding space and run deeply into it in the four seconds or so that he had before the orcs came? Another thing is that hobbits are not very fast as they have very short legs and are fat, and Sam had pots and pans with him which would have made lots of noise if he was running quickly, and we hear nothing.
Corrected entry: In the scene where Frodo, Sam and Smeagol crawl past the dead city of Minas Morgul, a huge green ray of light issues from the top of the tower, followed by a zillion and a half orcs marching out. In the shot where Gandalf and Pippin are watching this event from Minas Tirith, the green beam appears to be on the right (our right) of Orodruin (Mt. Doom) erupting. However, check out Tolkien's maps of Middle Earth and you will see that, from Minas Tirith, the green beam should be on the left of Orodruin.
Corrected entry: In the Tower of Cirith Ungol when Frodo is lying without his shirt, while they go through his clothing, he has spider web in his hair. A short while later when Sam comes to rescue him, there is no spider web in his hair at all, and his hands are still bound so he couldn't have removed it.
Corrected entry: In the Extended Edition Eowyn is asleep on a couch in the throne room of Meduseld after the Rohan victory celebration. But she lives in Edoras; why isn't she in her own bedroom? In the film she has to be in a public place, because otherwise Aragorn couldn't talk to her about her dream in the middle of the night. But would king Theoden really leave his eligible young niece asleep alone in the throne room, when there are lots of drunken guests around after the party? You'd expect at least a guard or chaperon with her.
Corrected entry: The first or second time you see a Nazgul riding the winged beast (in Osgiliath), the winged beast's mouth is big enough to fit a person in whole. Later on when Eowyn cuts the winged beast's head off (just before she fights the witch king), the winged beast's mouth is a lot smaller.
Corrected entry: After the battle of the Pelennor fields, when Pippin finds Merry, Merry says, "I knew you'd find me." Then in a side shot, though we hear Merry say, "Are you going to leave me?" his lips actually touch and come together like for the letter 'B' and NOT forming the letter 'L' in 'leave'. As an aside, it appears as if his lips may say, "Are you going to bury me?", which was the line as said in the book, but in any case still a mistake. (02:17:45)