Batman v Superman: Dawn of Justice caused a major panic at Warner Bros. The overwhelmingly negative response to Zack Snyder's pessimistic superhero slog spurred an instant desire to change the direction of the DC Extended Universe (DCEU) of films.

The studio decided its films needed to be breezier, more fun –not dour and brooding. The change greatly affected the final cut of Suicide Squad last year, and was vindicated by the critical and commercial success of Wonder Woman a few months back.

A root cause of the series' problems was Henry Cavill's Superman, who was cast as a reluctant figure that considered saving people a burden. That's not who Superman is, and not why people watch superhero movies.

Wonder Woman succeeded in large part because it grasped the concept of heroism. The film and character embodied a sense of hope and fundamental goodness that had been lacking.

Justice League understands this basic concept too, and that's the most noteworthy of its – very few – accomplishments.

Picking up where Dawn of Justice left off, Batman (Ben Affleck) is putting together a team of super-powered individuals to defend the world following the death of Superman.

Wonder Woman is on board, with The Flash (Ezra Miller), Cyborg (Ray Fisher) and Aquaman (Jason Momoa) not far behind. They've united to fight Steppenwolf (Ciaran Hinds), an entirely forgettable extraterrestrial villain with an even more forgettable plan for worldwide destruction.

When superheroes team up, they need a challenge worthy of their combined power, and Steppenwolf is not it.

1 of 4

Justice League marks the coming together of DC Comics' biggest heroes, but also the union of Warner Bros' old and new approach to the DCEU.

Director Zack Snyder has been the driving force behind the series to date, and was brought back despite Batman v Superman. He had to leave the film during post-production following a family tragedy, which led to Avengers writer/director Joss Whedon taking over.

Whedon and Snyder are two very different filmmakers, emblematic of Warner Bros former and future ideologies for making superhero extravaganzas. Whedon tinkered with Chris Terrio's script, oversaw reshoots and edited the final product, but Snyder still filmed the bulk of what Justice League is.

The result is a tug of war between distinct voices and tones that naturally creates incoherence. Terrio's script is undoubtedly dreadful – it's filled with ludicrous, nonsensical dialogue – but the very obvious Whedon witticisms sprinkled over it at least land with some success.

Affleck and Gadot lead a cast that does its level best with the material. Fisher is hamstrung as the po-faced and self-serious Cyborg, while Momoa's natural charisma comes through as Aquaman, a role he could excel in. The standout is Miller, however, whose Flash could become a future favourite with his planned solo outing.

There's a point in Justice League at which I was starting to think it might be a perfectly okay, routine superhero movie. Its first half skips along at a decent pace, the actors are doing a good job and there's some well-intended humour... but then things quickly take a turn.

A contentious idea debated by the assembled heroes takes the story into uncomfortable territory as the film actively, but awkwardly, works to retcon the sins of previous films.

A fairly simple film about superheroes coming together to defeat an apocalyptic threat then becomes a total mess. Misplaced gags, unintentionally absurd visuals, Henry Cavill's computer-generated upper lip and woeful lines of dialogue continually jar as the final act descends into a cacophonous of dreary special effects.

The sight of iconic heroes coming together should be as spectacular on a pretty basic level, but Justice League fails in this regard. The special effects are terrible, but even if they had been finished, visually there's nothing going on. This is a $300m (£227m) movie that is distinctly ugly, and that's unforgivable.

Our verdict
Justice League

Justice League looks dreadful, tells a dull story and includes a woefully misjudged second act plot thread, but it's still a significantly better film than Batman v Superman. Where Snyder's previous effort was a humourless grind, Justice League is at least brief, has some (scarce) character development and tries to enjoy a few laughs. It doesn't fix Warner Bros's superhero universe, but at least it fails with good intentions.