First off, let me say that for us JL purists, this is not exactly a Justice League film. Cyborg (Ray Fisher) didn’t get involved with the league until near the onset of the 21st century. Where are Green Lantern, Martian Manhunter (both scheduled for the sequel), Hawkman and The Atom? The villain here, Steppenwolf, was basterdised from a fairly new JL storyline, but was defeated thousands of years ago by a combined army of Amazons, Atlanteans, humans, and gods (who appear to have included at least one Green Lantern Corps member).
Batman (Ben Affleck) knows this from Lex Luthor’s notes left behind in “Batman vs Superman”, and he tries to put a team together with Wonder Woman (Gal Gadot) to defeat the villain. He goes to Iceland to track down Arthur Curry/Aquaman (Jason Momoa), who says he works better alone and turns him down. We later get reintroduced to Aquaman when Steppenwolf steals the Atlantean box. The three boxes are a source of pure energy that will allow the demonic villain to reshape Earth and replace humanity with his parademons.
Barry Allen/Flash (Ezra Miller) is more receptive. He is brilliantly cast here as a bit of a nerd. He tells Bruce he “needs friends” because he doesn’t quite get people. Also, he hates bugs , finds taller people intimidating, and has never been in a real fight, having mostly pushed people around. He becomes the film’s comedy relief.
There are plenty of violent but bloodless fight scenes, highlighted by crisp CGI effects and action that rivals any of the Marvel films. The script also is helped by a healthy dose of levity, such as when Barry asks Bruce what his super power is and Bruce replies “I’m rich”. After the villain is defeated with the help of the revived Superman, we cut to a shot of Bruce showing Alfred and Diana where the new League headquarters will be and end on a light note as Flash has challenged Superman to a race If this is the future of the DC universe, bring it on.