it is based off a graphic novel (fancy comic book) done by the same guy that made 'Sin City'. It is not supposed to be realistic, it is a heavily stylised take on historical events.
The "Spider Man" movies were based on comic books, as were the Superman movies and others. Often the dialog, acting, etc., was lacking, but the visual imagery was pretty decent.
Making a visual turd and calling it "a heavily stylised take" doesn't change the substance, it remains a visual turd. (Of course, I feel the same way about some of the "hip" TV shows where they insisting on tilting the camera from side to side.)
The story and acting will have to be awesomely good to make up for bad visuals.