Salient social commentary goes well with sympathetic aliens in this surprising sci-fi concoction. By the end I was rooting for the aliens. The pointed skewering of human behavior was spot on, though the aliens were not always portrayed in a flattering light as well; at their worst, they mimicked humans. The docu-style camera work was occassionally annoying, but the story and performances rang true, as well as the special effects. The ending was tied together well, and even the hint of a sequel made sense. Highly recommended if you're looking for brainy, satisfying sci-fi.
Its as faithful a rendition as could be expected of such a sprawling, complex novel (the most complicated graphic novel I've ever read). Occasionally clunky in its attempts to stay true, the acting and direction is uneven, though Haley as Rorschach, Morgan as the Comedian and Crudup as Manhattan were outstanding. Snyder was a tad too reverential, though I thought the ending was better than the original; the beginning and ending of the movie were the most cohesive, the middle too muddled.
As good as Heath Ledger's performance is--and he is, as you've heard, brilliant--the film exceeded my expectations. The moral questions it poses through its characters is as deep and thought provoking as any film I've ever seen. The entire cast is great. Christopher Nolan should receive some hardware for his direction, as should he and his brother for the script.