Perhaps it was the lateness of the hour and the fact that I was already short on sleep, but the liberties that Peter Jackson took with the story annoyed me in a way that even the change in Saruman's motivations in FOTR didn't. And unlike FOTR, where there were big cuts that the extended DVD could fix, there isn't a whole lot of room for the extended DVD to bail this movie out. Some extra Treebeard dialogue to get his characterization right, perhaps, and a Legolas/Gimli meeting after the Battle of the Hornburg to compare final scores, but the big cuts came at the end of the movie, and have obviously been relocated into Return of the King.
There were three arcs in the original Two Towers book. Peter Jackson obtrusively mangled one and a half of them, then crammed in a fourth arc involving elves that comes totally from left field and rings resoundingly false for all of the characters involved. The Merry-Pippin-Treebeard arc comes off the worst: the Fangorn Forest set feels completely wrong, the Ents look fake, Treebeard sounds like Gimli, and Jackson makes some rather major plot changes in a misguided attempt to ratchet up the tension and bring all three arcs to their climax simultaneously. Tolkien already intercut this arc with the events leading to the Battle of the Hornburg quite successfully, and here as elsewhere, Peter Jackson strays from Tolkien to his peril.
The Battle of the Hornburg itself has gotten quite a bit of attention from other fen, and is as spectacular as advertised. Jackson's simplifications actually work here: conflating Dunharrow with Helm's Deep actually adds to the suspense of Theoden's rehabilitation, though it does troublingly put Eowyn on the scene without allowing her into the battle. Conflating Eomer with Erkenbrand works in a Hollywoodish way, though the contortions that had to be done to fill in for Eomer's role in the battle felt a little jarring. But there's even some logic to the other major change to the Rohan order of battle given the absence of Dol Guldur in the films. Wormtongue is too over-the-top, Gimli is made too much the comic relief, and Gandalf's rehabilitation of Theoden lacks the subtlety of Tolkien's original, but in general, the whole Rohan arc is the strong point of the movie. Theoden is brilliant, and Eowyn shows promise for becoming so when she gets her big scene in the next movie.
The Frodo and Sam arc is well done up to the point when Frodo and Sam reach Henneth Annun. Movie-Faramir turns out to be the diametric opposite of book-Faramir, and decides to seize the Ring (!) and hand it over to Denethor. Frodo and Sam are marched into the battle for Osgiliath, and assorted movie-ish things happen until Faramir finally changes his mind and the Hobbits turn east again, at which point the arc recovers. Gollum is brilliant, and brings insight to the character that I'd missed even from multiple readings of the book.
And then there's the whole artificial Elrond-Arwen-Galadriel arc. The less said of that the better.
Anyway, perhaps I'm just tired and cranky, and seeing the film again this evening with friends might improve my mood about it. But from reading Tolkien's letters about other proposed film adaptations, he would've had a fit about this one.