If there's a perfect visual analogy for Guy Ritchie's ninth film, a CGI-heavy take on King Arthur, it arrives in the opening scenes. Giant elephants stomp across the land, with wrecking balls swinging from their trunks, smashing all that goes before them. Ritchie's latest – loud, brash and occasionally bold – does something very similar, rolling the Arthurian myths of Merlin, Mordred, Uther Pendragon et al up into a marauding beast of a movie.

Viewers would be advised to take some aspirin along: things get hella noisy, with Daniel Pemberton's booming score ringing out like a giant bell. Men shout, fight and scream – led by Charlie Hunnam's Arthur. A 'bastard son of a prostitute', or so he believes, the offspring of Uther (Eric Bana, seen in the prologue) is unaware of his royal lineage. Raised in a brothel, Arthur discovers his powers when he draws the sword Excalibur from its stone resting place.

On the flip side is Vortigern (Jude Law), the monarch – and Arthur's uncle – who killed his own brethren to claim power and now will do anything to maintain it. It's a classic set-up, of course, but Ritchie is insistent on adding plenty of his own spice to the mix. Rapid-fire editing, geezer dialogue and cameras swishing back and forth, it's like an ancient Lock, Stock. There's even a David Beckham cameo (no, really).

Featuring Aidan Gillen and Djimon Hounsou, it's a robust cast, with Law particularly good as the seething, rotten-to-the-core monarch. But, while the first half is promising, Ritchie gets waylaid by an increased use of digital trickery, as giant serpents, tree nymphs and even a slithery squid-lady come into play. Hunnam copes with the physical demands of the role, but even he can't survive amid all this chaos.

General release from Fri 19 May.