I was a little let down by the film. The source material was epic. The film was simply interesting. I think it was a valid effort, but the comic was way too deep to translate well into a film. I give them an A for effort though.
Without spoiling anything here's a few things I would've done to enhance the film...
1) Ozymandius. His costume didn't bother me, but the actor did. He wasn't very subtle.
2)Rorshach's origin scene was way too brief. An exact translation of it would've worked much better...and enhanced the movie's climax.
3)Nite Owl and Silk Spectre brutally beating the muggers...ummm what about that scene was heroic. It was way too over the top. Most heroes don't break limbs and murder muggers.
4)I don't mind the change ending. It worked in the movie's setting, but with that change Bubastis, Ozymandius' genetically created cat makes no sense. There was a whole genetic angle that was taken out of the film. This was fine, but Bubastis should've been taken along with it.
5)This one's gonna be hard not to spoil, but I'll do my best. The changed ending was fine, but the impact of the "big event" wasn't shown at all. When I saw the devastion in the comic, I got chills. In the movie you see some debris. It didn't really sink in.
Ok so those are my minor complaints. The film's greatest success in my mind, was the scene during the opening credits. I thought this was a fanastic way to introduce the audience into this world. I was really pulled in. I was a bit let down with the final product, but it was certainly a movie worth seeing.