King Arthur: Legend of the Sword, it might well say on the wrapper, but it might very well be the least King Arthury King Arthur movie ever made. The general shape of the thing is that of a Robin Hood story, particularly the 2010 Robin Hood prequel thingy with Russell Crowe. And if you're going to be reminded of any Robin Hood, that's the worst one.

So anyway, it's the familiar story of Arthur (Charlie Hunnam), son of the great King Uther Pendragon (Eric Bana - bland acting skills, it seems, are hereditary), who died in a coup orchestrated by his brother Vortigern (Jude Law). This happened just after Uther successfully destroyed the evil wizard king Mordred, and his army of 200-foot-tall elephants. Dropped, Moses-like, into a river, the boy Arthur is found by the prostitutes of a brothel in the prosperous ex-Roman town Londinium, and rises to manhood, picking up skills in martial arts along the way from a local Chinese monk named George (Tom Wu). By the time he reaches Hunnam-size, Arthur has become the quick-talking leader of a group of what I can only rightly call Cockney gangsters, including Wet Stick (Kingsley Ben-Adir) and Back Lack (Neil Maskell), the three of them serving as the brothel's guardian spirits.

Thomas Malory it ain't. That's not a "problem" per se; the fact that director & co-writer Guy Ritchie has arranged to re-imagine the Matter of Britain in the idiom of his own cheeky London gangster pictures of yore, Lock, Stock and Two Smoking Barrels and Snatch, is a bit charming, if decidedly ill-advised. In another world it's easy to imagine a version of Legend of the Sword that's delightfully campy in its horribly mistaken modernism, and plays up that campiness as part of its style. Sadly, Ritchie is a director for whom camp (at least, deliberate camp) is a completely foreign notion, and the weird, upsetting thing about Legend of the Sword is how very much the-opposite-of-fun it is. Ritchie takes it all much too seriously, which is a tricky enough thing to do in any film involving magic swords and characters with names like "Vortigern", and is I think entirely impossible to do when the film furthermore has an Arthur, King of All Britain, who talks like a tertiary character in a 1970s Michael Caine picture.

So anyway, back to the story: Vortigern is a paranoid tyrant, and when the lost sword Excalibur shows up in the bottom of a lakebed, plunged into a large stone, the evil king knows that a prophecy is afoot. So he rounds up all the young men of Arthur's approximate age to take turns pulling on the sword, and when it's Arthur's turn, you can guess what happens: a scene that resembles the Camelot legendarium. Anyway, Arthur is set to be executed after his triumph triggers a wave of revolutionary sentiment among the Britons, but he's rescued by a group of Uther loyalists: Sir Bedevere (Djimon Hounsou), Goosefat Bill (Aidan Gillen), Percival (Craig McGinlay), Rubio (Freddie Fox), and a nameless female mage (Astrid Bergès-Frisbey), an acolyte of the great, mysteriously hidden Merlin. Together with Arthur's gang, they plot to overthrow Vortigern's corrupt government and install Arthur as the rightful king.

It's weird as hell, lacking anything that really clearly would appeal to the people for whom plugging the words "King Arthur" into a movie's title counts as a draw. Presumably, the actual kinging would have taken place in some or all of the five planned sequels that are surely never going to see the light of day now, and I'm baffled and terrified that anybody ever thought that was a reasonable thing to set up in advance. Anyway, the fact that this is basically non-Arthurian in the extreme is more of a curiosity; it's still possible to imagine some version of this story working. That version would have had a substantially different cast: I can't think of anybody with a sizable role that's legitimately good in the role, though at least Hounsou, Maskell, and maybe Law avoid humiliating themselves. Hunnam is, to be fair, undone by a role that has been written to be completely unplayable, so it's not fair to lay the blame directly at his feet; still, he's got nothing much to offer but good looks, and even those aren't much to speak of in the firmament of blond guys with British accents (let us all agree, though, that Hunnam is much better when he can use his British accent than when he's struggling to put on an American one).

But any decent Legend of the Sword would absolutely need a do-over on everything to do with its style. It's got some killer special effects - it might have cost far too much, but the money showed up onscreen - but a manner of editing scenes together that's hellbent on making those visuals impossible to see clearly. Some of it's just the normal 21st Century "let's cut the action together much too fast for absolutely no purpose" bullshit, but generally, it's much more inventive in how restlessly and antic all of it is. Conversations jump back and forth from present to flashback (or flashforward - or flash-alternate-universe), adding a level of kinesis that must have been a lot of fun to imagine and shot and edit, but is too manic and wearying in the viewing. A few times, thankfully only a few, the film ramps the speed up or down, going all Zack Snyder on us, and of course you never want a movie to go all Zack Snyder on us.

What's particularly irritating is that these flourishes of high-speed filmmaking are used very sparingly indeed, which leaves the film without any consistent aesthetic sensibility. Sometimes it's unpleasantly fast, much more often it's unpleasantly sluggish, creeping forward with its non-story by minuscule inches. The one thing it never manages to be is correctly paced to draw us through the story at an urgent clip without strapping on the rocket boots.

Meanwhile, the film indulges in some weird design peccadilloes: an obsession with snakes and snake-like things, for one, those kitschy gigantic elephants for another, and costumes for the bad guys that reach Star Wars levels of anti-subtlety in putting all of the wicked people in shiny black. The results are one hell of a hokey, overdone fantasy, and not all the gravity of performance or of direction can salvage it. The film is utterly monotonous despite being mindlessly busy, and when you have something this over-the-top in its caffeinated laddish enthusiasm for swords, monsters, and magic, monotony is a particularly galling sin.