Just saw this, it's ok, but it's not long enough. It feels like I'm watching an episode of a cartoon rather than a full length movie.
The side characters aren't expounded upon enough. The twist is predictable, the pacing is rushed, too many gaps and jumps between character relationships. This could have benefited from another hour of exposition and actual standout fight scenes.
I have no experience with the source material so I can't comment on the accuracy of it, but it needed more than it got. All of these newer DC films are going to probably fall flat if they stick with being under 90 minutes because that's just not enough time, especially for a movie with this many new and unfamiliar characters.