The battle scenes are very impressive given the early-2000s CGI work. Many of the action sequences feel like a fitting payoff after longwinded portions of the first film, but the dialogue is rather forgettable at times here.
This would probably be my second favorite in the trilogy if we could just edit out Peter Jackson's ill-advised attempts at humor, like the Gimli short jokes and Legolas surfing down a flight of stairs. Otherwise, the battle at Helm's Deep is as good as action gets in Lord of the Rings: not as epic in scope as the battle in RotK but much more intimate and personal of a fight, and therefore more exciting to watch.
(EE) Post-read, this moves at speed, trading literary moments of heart for plot pace so they keep cutting scenes, which is acceptable, but they also ADD pointless crap (Rohan refugee children, Wargs) and arbitrary plot and character changes. There isn't really any need to change something that's a fucking masterpiece. But still, it's crafted incredibly and the invented Arwen and Aragorn scenes steal the show somehow.
Surprisingly, a dud. Endless grey monologues, pointless side-plots, key uncharismatic performances from, to start with, Hill and Otto. None of the wistful earthiness and even passion of the first film (perhaps due to the absence of Bean and Holm). Brad Dourif's small role as Grima Wormtongue is so good that the film plunges into dullness on his departure. The reliablity of Wood and Astin bring the only solidity.
The strongest of the three - a perfect balance of relational, emotional, and plot-driven drama. Much more subtle than the others, with Andy Serkis and Bernard Hill stealing scenes left and right and powerful performances also by Viggo Mortensen, Miranda Otto, and Sir Ian McKellen. A beautiful climax that still makes me weep after 10 years of viewing.