I have to say, going in I hoped for something much nearer to the graphic novel, and I was quite let down by how little it adhered to what felt like an exceptionally well-crafted and impressive comic book. That being said, I don’t demand absolute faithfulness to the source material. Still, it's better than a lot of the previous Batman films; it does succeed in presenting a worthwhile narrative and providing glimpses into the Joker's shifting and often contradictory history, despite skipping over quite a bit of it. Ultimately, particularly when considering modern entertainment, this film serves as a recollection of how wonderful comic books once were, and could be again if they began focusing on telling genuine stories.

Source on TMDB