Last year, Muse frontman Matt Bellamy announced the band's sixth album would be a "Christian gangsta-rap jazz odyssey, with some ambient rebellious dubstep and face-melting metal flamenco cowboy psychedelia". It tells you something about Muse that it was hard to work out exactly how far his tongue was lodged in his cheek. For one thing, it's almost always difficult to work out how far Bellamy's tongue is lodged in his cheek, as when he told NME he believed in the theories of Zecharia Sitchin, whose big idea was that the human race had been genetically engineered by aliens from the planet Nibiru, or cancelled a series of US interviews on the grounds that he'd heard an asteroid was about to hit America. For another, if any currently extant major band were to be engaged in creating a Christian gangsta-rap jazz odyssey, with some ambient rebellious dubstep and face-melting metal flamenco cowboy psychedelia, it would probably be Muse. Comparisons are regularly made between their oeuvre and that of Queen, Rush and Radiohead: there's an argument that Muse are to pre-Kid A Radiohead what Meat Loaf circa Bat Out of Hell was to Bruce Springsteen. But none of them really capture the sheer level of trenchant preposterousness at which Muse operate. The most apposite comparison might be to say Muse have actually achieved what the Darkness set out to do: conquer the world with music that's clearly meant to be funny, but isn't supposed to be a joke.

Indeed, it could be suggested that the only real giveaways to Bellamy's comic intent were that his bandmates were talking up their forthcoming album as a major sonic reboot – "It's time to move on and do something radically different," suggested bassist Chris Wolstenholme – and that his description didn't actually sound that far removed from what Muse had done previously: they'd already achieved something best described as "metal flamenco" on 2006's Black Holes and Revelations. That said, anyone listening to Supremacy, the opening track of The 2nd Law, might wonder precisely how radical a reinvention Muse have undergone.

The understated single Madness suggested a new stripped-back approach: there's not much to it beyond an electronic bassline, a decent pop song and Bellamy's vocal, which declines to unexpectedly burst into an ear-splitting falsetto (or scream), or proclaim the imminent arrival of the apocalypse, or indeed do any of the things he usually does within seconds of getting near a microphone. But clearly any discussions about toning it down a bit were shortlived. Supremacy's musical DNA is equal parts Led Zeppelin's Kashmir and Wings' Live and Let Die: its idea of restraint is to leave it a minute and a half before bringing the choir in. It should be noted that, Madness aside, The 2nd Law's lowest-key track is Animals, which concludes with what sounds like a recording of a riot in full swing.

In fact, the most obvious sign of change on The 2nd Law is its incorporation of the kind of dubstep produced by Skrillex and dismissed by its detractors as "brostep". It actually meshes with Muse's existing style remarkably well, perhaps because Muse and your average brostep producer are cut from the same cloth in at least one sense: neither of them has much interest in subtlety. Unsubtle or not, the concluding two-part title track – the most obviously brostep-indebted thing here – is thunderously exciting stuff, a boiling mass of fidgety strings, electronic voices and sub-bass wobble.

This is obviously all great rollicking fun, but there are problems with The 2nd Law. You can see why the organisers thought Muse would be the right band to provide the official song of London 2012, but Survival didn't work – partly because it seems to have no tune whatsoever, but mostly because it didn't fit the event. The Olympics turned out to be as much about tiny human stories – from Chad le Clos's dad to Kirani James and Oscar Pistorius swapping nametags – as epic spectacle. With their choirs, string-laden intro, hysterical vocals and lyrics you might characterise as a bit Ayn Randy – "I chose to survive whatever it takes … vengeance is mine … Fight! Win!" – Muse got the scale but missed the humanity. Six albums in, this is a recurring problem: amusing and enjoyable as the aural histrionics are, you do start to wonder what, if anything, they're trying to express, or if it's just bombast for bombast's sake.

Occasionally, you get the sense the band's sound is actually antithetical to genuine emotional impact. Follow Me is a song about Bellamy's baby son: "I will keep you safe, I will protect you, I won't let them harm you," he sings. He obviously means it, but delivered as it is, in a portentous voice that leaves teeth-marks on the scenery, to a backdrop of distorted dive-bombing bass (courtesy of co-producers Nero) and florid synthesiser arpeggios, it sounds like he doesn't. Similarly, it's hard to tell whether there's actual political conviction behind the title track's equation of the second law of thermodynamics with global economic collapse, or if it's just showy grandiloquence, a lyrical counterpart to one of Bellamy's more baroque guitar solos.

None of this stops The 2nd Law from being a hugely entertaining album. Nor will it stop it being a vast success. After all, no one goes to see a blockbuster for its profundity and deep characterisation. They go for the stunts and the special effects, both of which The 2nd Law delivers.