For a band who've spent the best part of three and a half decades trying to make a virtue of haphazardly breezing through disparate genres, you'd think Primal Scream would have stumbled upon one they liked the sound of. Or, at the very least, a few that played to the strengths of gruff frontman Bobby Gillespie & Co. and their itinerant spirits. For those not familiar with their canon, they've toyed with everything from day-glo pop (Beautiful Future) and garage blues bar-boogie (Riot City Blues) to the angry, aggressive industrial dance of XTRMNTR and a whole lot in between. It's an approach that has occasionally been spectacularly successful – dragging most of rock & roll history into the Pills'n'Thrills-era Hacienda and letting Andrew Weatherall referee the ensuing scuffle resulted in one of the last great totems of independent music – but one that's also been their greatest weakness.

After all, there are only so many times you can use dubious cover versions featuring Kate Moss and pseudo-intellectual utterings – "It's an anarcho-syndicalist speedfreak road movie record!" – to cover up musical shortcomings. They've been treading water for a good few years now, diminishing returns propped up by a legacy that few seemingly want to relinquish, including the band themselves; wringing ever last drop of nostalgia from the 20th anniversary of Screamadelica is exactly the sort of thing that would have enraged the young Gillespie. Which brings us to Chaosmosis, album number 11, and a supposed return to form (although what "form" sounds like for Primal Scream would be as hotly debated by their detractors as by their fans).

Never mind the nonsensical portmanteau of the title, or the eye-gougingly bad cover art, things only get truly ugly when you hit play and sit back hoping to be entertained. "C'mon!" intones Gillespie, sounding like the last man standing at closing time. "Everybody now…Go! Get ready!" A familiar-sounding piano loop kicks in, backed by fuzzed out guitar and bongos, and it's as if the halcyon days of Madchester never ended. As a tribute to their magnum opus, it's pretty limp, the presence of HAIM neither a help nor a hindrance, but at least the band sound like they know what they're doing. Elsewhere, the scattergun approach previously reserved for entire records has been applied on a song by song basis, so much so that I had to keep checking that iTunes hadn't skipped to a different artist entirely.

Taking on a brief to be inventive, to try new things, should of course be applauded, but here Primal Scream sound like a band in the midst of an identity crisis. From the eight-bit techno of 'Carnival Of Fools' to the breathy acoustic folk of 'Private Wars', each new idea sharply pulls them off on another tangent; this is one of those albums that ends up as less than the sum of its parts. By the time you get to 'When The Blackout Meets The Fallout' – sounding for all the world like an offcut from the Matrix soundtrack – and the plodding indie-landfill of 'Autumn In Paradise', you're left wondering exactly who was in charge, and who thought all of this was a good idea.

Gillespie the firebrand had a purpose and was laser focused on the targets of his ire; it's no surprise that such anger helped produce their best work. Back then Primal Scream had a searing, rampaging quality, as if the band were trying to keep up with Gillespie's venomous delivery. Nowadays he just sounds tired, or even worse, uninterested, slowly mooching from song to song. His vocals, never particularly stirring at the best of times, sound even thinner and detached than normal, a reedy whine that, when combined with his sub-sixth form poetry – "As sure as sin/Peace begins within" to give just one particularly pungent example – fails to generate any friction or emotion whatsoever; so much here scans as pointless platitudes floating through the music.

Primal Scream always sounded like a band ready to go to war, one that wholeheartedly embraced the craziness that frequently engulfed them; teetering on the brink seemed to always inspire them to ever greater heights. Maybe losing Mani fatally compromised their drive, maybe the years of excess finally blunted their edge. But there was a time when Primal Scream were considered essential, an acclaimed element of the indie rock landscape, and more than anything, Chaosmosis simply confirms that those days remain firmly in the past.