Watchmen was ridiculously faithful to its source material, something required for a work that means so much to so many. Which made it a bit like reading the graphic novel for me. And I think that's the point. It was an incredible movie based on an incredible graphic novel. But it didn't really add or change anything with its change to a new medium. Which is probably fine. But I find myself asking what the point was, exactly. Kind of like remaking Psycho. If you don't make any real choices, are you really making a separate work of art? Having said that, I thought the very few divergent choices that were made seemed to be made at random and for no reason (take the "practical joke" at the end, for instance. A claim has been made by Brock Sampson that it would take too long in a movie to explain the ending from the book, but I don't buy that. I think that they take the same amount of time to explain. So it was just random for me, but, maybe, this is exactly the sort of choice I want to make it a different work. The movie, on some level, makes more sense and a better point than the book does because of this change to the ending. So.). On the other hand, the choices that had to be made, like with the soundtrack, were made extremely well, in my opinion. Am I thinking too much about this?
Perhaps I'm too harsh to a movie that I thoroughly enjoyed (and saw twice yesterday in IMAX). I thought this movie was great. The casting was excellent and even the one I didn't like (Veidt) got better upon a second viewing. It was well-acted and well-shot. Just good.
To speak to both the book and the movie, I believe that what makes this not only good, but important, is that it takes as its subject the unimaginable horror that men are capable of and it shows that, on the other side, even the men who fight this horror are often engulfed in it and imperfect (to say the least) in their pursuit of better things. It tells a human story - horrible, dark and troubling, but with incredible meaning and great hope brought about from the most Faustian decisions possible. I still don't know what I think about the events of the story and I've read it once and seen the movie twice.
And Melissa, to answer your question: these superheros are like the new Batman - good technology plus good workout routines and training make you stronger and better than your opponents. But these are still men and women, mostly (even the blue guy used to be human). Apparently, properly motivated and trained human beings can kick the ass of a whole string of villains in a dark alley or a prison. Also, it doesn't hurt to be a sociopath, like Rorschach.