I'd just like to say that this movie kicked ass, and everybody with at least some culture should go out and see it. I know that this excludes 90% of America, but I thought that I'd at least get that out there.
Casting was well done, good special effects that didn't have the Matrix-like overabundance. Pacing was good, cinamatography was great, set & costume design was excellent; overall all the things one needs for a great movie.
The problem is that I'm pretty sure that most of the people who will see this movie won't have a damn clue who half the characters are. And won't be able to appreciate the old school cheesy adventure style that this movie pulls off wonderfully.
Naturally as a fan of the comic I have a few gripes with characters that were added, changed, or left out completely. Though for the most it was only the two core changes made to Quartermain and Helmina's characters that really bothered me.
Big three fun things for the movie was the unbeliavble sexyness of Dorian Grey (The Immortal), and the ultimate badassness of Cap. Nemo (please tell me that at least SOME of you have read 20 000 Leagues Under the Sea). And Sean Connery was really the ONLY man to play Alan Quartermain (unless you get the guy that played him in the old Hunter movies).
Overall I say that the nay-saying critics can go toss off, b/c they don't know their asses from a hole in the ground; they're just more pop culture midgits with a paid opinion.