It’s not terrible; at no point does it reach the lows of “Batman v Superman: Dawn of Justice”. It’s not great, either; the film never reaches the highs on par with Marvel’s best films. It was… pretty good!
Despite the success of DCEU’s “Wonder Woman”, “Justice League” wasn’t quite able to follow it up with another film that connects with the audience. The main issue of the film is that it feels disjointed, with some sudden shifts in town, and underdeveloped characters.
The shifts in tone can be attributed to a substantial portion of the film having been shot by Joss Whedon, who filled in for director Zack Snyder, who had to drop out six months before the film’s completion due to a family tragedy. There were distinct moments where anyone who is familiar with the two directors’ work would go “oh, that’s got to be a Snyder shot”, or “oh that’s a signature Whedon” moment. And while that would be fun to do for the audience, it doesn’t really help with the film’s storytelling.
The film also suffers from a short (yes, short!) run time, as the studio demanded that the film be no longer than two hours, mostly for financial reasons. For the “Avengers” equivalent of the DCEU, and not having introduced a few of the main characters in previous films as Marvel did, two hours was definitely not enough to introduce new characters AND tell a coherent and entertaining story. I don’t mind a film being long as long as it’s good; “BvS” was long but it was not good. If Justice League had to be 2.5 hours but we got a better film, I’d be totally down for it.
As a result of its relatively* short run time, newcomers The Flash (played masterfully by Ezra Miller) and Aquaman (played by the fierce Jason Mamoa) come off as thin characters, and the developments of Batman and Wonder Woman come off as incomplete.
Yet, although the film suffered from the aforementioned flaws, it’s still a fun ride at the theater. I had a decent time watching it; there were certainly a few standout moments that made the experience worth it.