Errores

In the first shot of the orc attack in Moria, Legolas' bow is tall with spiral tips (which he uses throughout the movie). In the very next shot, two seconds later, it is much smaller, with the regular curved tips of a straight-limb longbow.

When Gandalf comes into Bag End after Bilbo seals the envelope, the door is open to the left with the doorknob on the right. But when Frodo opens it to see Gandalf and let him in, the door now opens to the right with the doorknob on the left side.

The hair colors of Merry and Pippin keep changing throughout the film as the colorists kept confusing them with each other.

The night Boromir tries to persuade Frodo to lend him the ring, the moon is behind Frodo, but it is also behind Boromir as well.

The same close-ups of Legolas firing his bow and then running appear twice each during the Helm's Deep sequence.

The Dwarf Gimli is almost as tall as the human and Elven characters in this movie. Presumably the actor who played him in the live-action footage was insufficiently short, and it was considered impractical to shrink him in the rotoscoping process.

When Frodo yells "Go back!!" to the Black Riders before he flees them to the Ford of Elrond, there is noticeably a different voice actor with a higher pitched voice saying the line and not Christopher Guard, Frodo's actual voice actor.

In many, many shots throughout the second half of the movie, the blond Legolas has dark hair. The actor who played Legolas in the live-action footage on which the movie was based clearly had dark hair, and these shots were insufficiently fully converted into animation.

As the Orcs chase the characters across Moria shortly before the Balrog appears, there's a shot that only shows the background without the Orcs for a few frames before the Orcs pop into existence.

The name of the wizard of Isengard fluctuates between "Saruman" and "Aruman" throughout the movie.

Celeborn's name is mispronounced ("Seleborn" instead of "Keleborn").

"Minas Tirith" is consistently mispronounced as "Mine-as Tirith" rather than "Min-as Tirith".

Saruman is called "Saruman the White" and "Saruman of Many Colors", yet throughout this movie he is dressed entirely in red.

Gandalf and Aragorn pronounce "Edoras" differently.