I thought this was very much a comic book, even on the big screen. I haven't read the original but you could see that a lot of the set piece kind of shots were lifts straight from panels of the comic (pushing the persians to the cliffs, the shot from behind Leonidas right at the end). The camera has the same kind of over the top graphic novel melodrama that the writing and the acting have. That's not a criticism because it really works in the right kind of film, which is this kind.
It got kind of bogged down with the politics in the middle, and it felt a little like it was there just to give the film a sheen of legitimacy rather than being a montage of fights. All in all though B+ would watch again.
PS
If you are that way inclined you could read a more detailed dissection
here