Please do not refer to "The Two Towers" as a sequel. Think of it as simply the middle of a very long, but exceedingly excellent, film.
Ultimately occurring in the middle of "The Lord of the Rings," "The Two Towers" darkly and violently portrays the hero, in this case Frodo Baggins, facing the greatest obstacles standing between him and his quest to destroy evil. External and internal forces threaten to tear him apart as the ring begins to take hold over his very soul.
"The Two Towers" does indeed - like the original source material - drag in spurts. Fortunately Peter Jackson willingly allows exposition and character development to enter into his narrative. This allows a greater sense of urgency and viewer empathy to underscore the sweeping battle scenes (found here in great and glorious multitudes).
"The Lord of the Rings" has always stood as an effective, Christian-driven, Jungian-infused classic battle between good and evil. A strong historical subtext also resounds throughout the film. The World War II imagery rings loudly in the hollowed-out ruins of Gondor, looking much like a besieged Leningrad, or bombed out London. J.R.R. Tolkien also allows some not-too-subtle Luddite soapboxing declaring the evils of industry and technology to filter through the sword fights and heroic daring-do.
"The Lord of the Rings" also advertises the natural wonders of New Zealand far better than any tourism board could hope to achieve.
"The Lord Of The Rings: The Two Towers," the middle installment in what eventually will become one of the greatest achievements in film history, gratefully ends one of the worst years in film history. Watch, enjoy and savor.