Grade: B-

After some early missteps in its attempt to challenge the Marvel Comics cinematic juggernaut, the so-called DC Universe finally scored big with its last entry “Wonder Woman,” and with “Justice League,” its answer to Marvel’s “Avengers” series, it can boast another modest success. The picture is still visually too dark, and it’s hobbled by a villain who’s a crashing bore, but it adds a welcome dose of humor to what had been pervasive grimness, and some promising new characters as well. Whether responsibility for the lightening of tone should primarily go to Zack Snyder, who’s overseeing the DC franchise and is credited as director, or to Joss Whedon, who is listed as co-writer and supposedly did reshoots after Snyder left to deal with a domestic tragedy, will probably be a matter of continuing debate. But the important thing is that the result is surprisingly enjoyable, and as edited to under two hours by David Brenner, Richard Pearson and Martin Walsh, mercifully short as far as superhero movies go, too.

In the aftermath of the disappointing “Batman V Superman: Dawn of Justice,” the Man of Steel is dead, and his demise has cast a pall on humanity that invites the return of an ancient enemy of earth, gruesome destroyer Steppenwolf (Ciarán Hinds, as unrecognizable as the equally heavily made-up Oscar Isaac was as Apocalypse in the last “X-Men” movie). He’s a figure from DC mythology about the realm of the evil Darkseid, and returns to terra not-so-firma seeking three all-powerful boxes that apparently can gobble up planets when linked together. He lost them on his first invasion many millions of years ago, when mankind, the Amazons and the inhabitants of watery Atlantis banded together to defeat him. Each group took one of the boxes to guard.

Now Steppenwolf is coming back with an army of flying parademons that feed on fear, and Bruce Wayne/Batman (Ben Affleck) senses an impending invasion. To deal with it, he recruits a league of people with special powers. The first is, of course, Diana Prince/Wonder Woman (Gal Gadot), whose number he has from “Dawn of Justice.” He is, on the other hand, initially rebuffed by Arthur Curry/Aquaman (Jason Momoa), who prefers remaining a gruff loner, and Diana also gets the cold shoulder at first from Victor Stone (Ray Fisher), an injured young athlete whom his scientist father (Joe Morton) has saved by turning him into surly Cyborg—using, it turns out, the human-held box that Star Labs, where he works, has somehow gotten hold of. By contrast young Barry Allen/Flash (Ezra Miller) gleefully accepts the offer to enlist; he’s a guy who longs for cool friends.

A good deal of the movie is devoted to these recruitment efforts, which are amusingly depicted in the cases of Aquaman and Flash. (The Cyborg thread, at least in the early stages, is presented rather glumly, in the fashion of the pre-“Wonder Woman” installments in this DC series.) But eventually all five unite after the boxes held by the Amazons and the Atlanteans are taken by Steppenwolf, though not without occasional bursts of dissension among them. Unfortunately their first encounter with Steppenwolf does not go well, and they find themselves in need of additional power if they are to have any chance of saving earth. That’s why they decide to put the human-held box to use in order to…well, we shall leave that for you to discover for yourself. (Just check the cast credits for a clue.)

One of the particular pleasures of “Justice League” is that when the final confrontation comes, it’s in a nearly deserted area of Russia, a place left desolate by a nuclear accident obviously modeled on Chernobyl. That means that we don’t have to put up with the tired cliché of collapsing buildings and bridges as cities are reduced to rubble in an overly-familiar climax. To be sure, there is still plenty of CGI work on display here, and the culminating battle between heroes and villains is done in typically dank style (cinematographer Fabian Wagner and production designer Patrick Tatopoulos really lay on the gloom). But the number of potential human victims that require saving is relatively small (basically a few families that have been squatting in some condemned buildings), and the smaller scale in that respect acts to, rather than detracting from, the sense of human involvement.

As to the cast, even Affleck and Gadot crack occasional smiles this time around, and Jeremy Irons makes a reliable Alfred, with Amy Adams reprising her Lois Lane and Diane Ladd her Ma Kent. In his scenes as Superman, Cavill seems to be mellowing as well. But one has to feel for Hinds, stuck in some of the most unattractive costuming this side of gargoyles and barking out lines that would be absurdly overwrought even in a fifties comic.

On the other hand, Fisher, after opening scenes in which he tries to outdo Affleck for dourness, opens up nicely in the picture’s latter stages despite his heavy makeup and costuming. And Momoa and Miller are both winners. The big fellow portrays Aquaman as a lumbering, slightly dim guy in the manner of Chris Hemsworth’s Thor, with a scene involving Wonder Woman’s lasso that’s a great bit. Miller uses his comic chops to the hilt, not only delivering his quippy dialogue with cheerful new-kid-on-the-block enthusiasm but putting some welcome goofiness into his action scenes as well—including one of the extras inserted into the final credits (an addition that fanboys will especially appreciate as a salute to a frequently recycled DC topos). You can compare his Flash to the similarly upbeat take that Tom Holland gave Spider-Man in the last “Avengers” flick, as well as look forward to the solo movies promised for both Aquaman and Flash.

“Justice League” closes with nice summing-up moments for its various characters, as well as a closing blurb pointing to what’s planned for a JL follow-up. If this movie is any indication, one can anticipate that continuation with a lot more hopefulness than you possibly have for a second helping of something like “Suicide Squad.”