Justice League: Dark is yet another DC DTV movie set in their revamped universe based on the "New 52" comics imprint. While the movie is set between Justice League vs Teen Titans and Teen Titans: The Judas Contract and follows the same continuity it's not directly related to neither, being a standalone side story. It's also, easily, the best of these movies until this point since the revamp, and for now the one I can see myself rewatching multiple times.
The story is as follows: all over the globe people are hallucinating others as if they were demons and monsters, causing irreparable physical and psychological damage to them and themselves. The Justice League reasons this is a mystical attack, so Batman decides to recruit the help of occult detective John Constantine in order to figure out the origin of this attack. Due to the nature of the situation, other mystical beings join the quest, temporarily forming the titular group, the Justice League Dark, as they work an uphill battle to stop the threat before an increasingly powerful villain brings humanity to its end.
Unless you happen to be one of the three people on the planet who's not familiar with Batman, you don't need to have watched any of the previous movies to understand any of these characters. All of them are well introduced and given their due. The villain manages to be quite impressive and scarily powerful. The stakes are quite high, and it's shown. It's also a film in which victory comes at a high price, and things don't neatly return to the status quo once it ends.
There's really a lot to like about this movie. The action is great, and the animation does it justice. Voice acting is pretty much top notch as well. Also, the movie doesn't waste any time with unneeded scenes, silly slapstick or irritating pop songs, like previous movies in the series would do. It's great that this movie pays attention to the often-overlooked mystical side of DC, and the fact that Batman isn't given top attention, even if the movie could easily justify it, is fantastic. I love Batman, but DC tends to be unable to show restraint with his presence.
The extras are on par to what these movies tend to offer. I am a bit sad that at some point they decided to include just 2 bonus cartoons from previous DC animation rather than 4, but the rest of the stuff is still interesting. Though I'm a bit puzzled to the inclusion of "sneak peeks" to a couple of movies that have been released years before. Also, it's curious that one of the features is dedicated to the team member with the least screen time while there's none dedicated to two of the most important ones.
In any case, I most definitely recommend this film. Probably not to children, though. They might get a kick out of the action scenes, but the general tone of the movie and the characters need a more developed mind to be appreciated. Not to mention that there are some things that might definitely scare away younger kids. Everyone else should check the film, particularly if you're into magic and sorcery.