There are some good to excellent animated superhero/comic book films out there. 'Justice League Dark' is not one of the best of them, but it is nonetheless a worthy effort. People will either love it, be disappointed in it or find a lot to like while finding things that didn't work, there's a bit of all three going on here.
'Justice League Dark' is somewhat too short, 75 minutes doesn't seem anywhere long enough for a film with so many characters, rich themes and a very densely structured story. As a consequence, some of it is a little rushed and there are instances of parts in need of more exploration or characters having nowhere near the amount of screen time they deserved (Swamp Thing is one of the biggest wastes).
Most of the voice acting is fine, others not so much. There could have been more variety in some of the female voices and while good as Brand Nicholas Turturro's voice doesn't fit Deadman's personality or look. Oh and the villain Destiny is underwhelming, too underwritten, weak motivations and defeated too easily.
However, to me, the animation was not a problem. The atmospheric colours and fluidity are simply remarkable. The music is haunting and beautiful at the same time, giving intensity to the action scenes and giving weight to the more emotional and dramatic scenes.
Dialogue is smart and intelligently written and while the story isn't perfect it's absorbing and thematically interesting, with intriguing use of mythology and mystery and celebrating in a fun way the supernatural elements. Constantine and Zatanna, and their chemistry, are particularly well done.
Not all the voice acting works, but most of it does just fine. Matt Ryan and Jason O'Mara (filling in giant shoes with aplomb) are perfect as Constantine and Batman. Roger Cross, Enrico Colantoni and Rosario Dawson are also very good fits. Whatever reservations there are with Destiny, Alfred Molina's voice work is not among them.
In summary, falls short of being great but has a lot of impressive elements that make it worthy. 7/10 Bethany Cox