First of all, Tolkien's The Lord of the Rings
-trilogy had to be made a movie---no self-respecting filmmaker could review Tolkien's text and not want to make that movie.
That brings up one of the movie's faults: that it had to be distributed in three parts. I can understand the theater releases---because no one wants to sit in a theater (not even a well-built, stadium-style, hottie-run theater) for 6-9 hours! And the books were understandably seperated to make it easier to write reports on them.
But if you've got the stuff at home for more than 48 hours, you don't need WHOLE BEGINNINGS AND -ENDINGS to manage your time!
And even if they though the theater-displays and super-short rental-periods would somehow outweigh the personal purchases UNTIL THE END OF TIME, they didn't have to wait nearly a year between releases!
The acting was so good that I noticed a couple of screw-ups, including:
--when Frodo (Elijah Wood) tells Sam (Sean Astin), "That's what I like about you, nothing ever seems to get you down," Sean should have (but didn't) looked at least a little happy before he turned and saw the clouds approaching.
--When Gandalf (Ian McKellen) was telling Treebeard about Saruman's now-lack of power, something tells me he should've seemed more unsure of it.
--Maybe there were more screw-ups, but I was too enchanted (by Liv Tyler and by Miranda Otto's cheeky chin) to notice.
The moviemakers had little to do with shaping the story; that ball was entirely in Tolkien's court. Being a professor of mythology, I suppose he couldn't have written anything better---not if he had wanted it to last as long as it has.
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