Order trumps chaos in the latest adaptation of a DC Comics series. Suicide Squad works hard on churning out manic energy through a collection of mayhem-loving villains who are sprung from prison in order to defeat a rampaging witch, but it is Viola Davis’s calm and collected Amanda Waller who towers over the proceedings.

Ruthlessly focused on protecting the United States of America from harm, even if it means risking the lives of innocents, Waller is the real villain in this poorly stacked deck of cards. She is played with steely wit and controlled menace by Davis, and is the most impressive character in a movie that careens between highs and lows and squanders its early nihilistic promise with flat writing and humour and standard-issue action set pieces.

Conventional logic is typically turned on its head in comic book adaptations, but Suicide Squad is even more lazily plotted than the average saviours-in-tights saga. Waller assembles a demented version of the Avengers and the X-Men to take on the malevolent Enchantress (Cara Delevingne), who has escaped captivity and wants to destroy New York City. The crew’s members include ace shooter Deadshot (Will Smith), the self-evidently named Boomerang (Jai Courtney), the fire-causing El Diablo (Jay Hernandez) and the reptilian monster Killer Croc (Adewale Akinnuoye-Agbaje). Harley Quinn (Margot Robbie), a former psychiatrist who has lost her heart to the Joker (Jared Leto), adds sass and sexiness to the all-male pack. Robbie’s lines don’t cut as deeply as intended, but her outlandish sartorial and make-up and put-on cuteness provide the film with much-needed levity.

Waller coerces the diverse group to take on the Enchantress, who has reincarnated her brother Incubus (Alain Chanaoine) and is building an army of monsters to destroy the city. Since these wart-covered creatures are shown to be easily destroyed by the impressive weaponry and bombs of the American soldiers, led by the stolid and honourable Rick Flak (Joel Kinnaman), it’s never clear why the amoral Waller simply doesn’t nuke them at the onset. She seems perfectly capable of doing so.

Jared Leto’s much-hyped Joker is less an agent of destruction and more of a distraction from the predictable antics of the rest of the squad. Leto works hard on differentiating his character from Heath Ledger’s definitive Joker from Christopher Nolan’s The Dark Knight, but blood-red lipstick and chain-like dentures cannot compensate for a poorly written character who appears to saving his best for the inevitable sequel.

Director David Ayer’s on-the-nose writing spells out what is obvious – that Waller is the squad’s real tormentor – and a character even helpfully talks of “honour among thieves”. Suicide Squad doesn’t trust its instincts for mischief and derangement enough. The contours of a truly mean and subversive comic book adaptation flash through in some portions of Suicide Squad, especially when Waller and Harley Quinn are around, but they are defeated by the curse of the ultimate Enchantress – the please-all Hollywood blockbuster.

‘Suicide Squad’.