"Opus Alter proudly takes up the torch from its forebear, Opus Primum to form the second half of ORO, an exploration of 'knowledge and power' the band insists should be approached as one whole experience. And altogether, it works; the two halves complement each other effortlessly, combining to create one enormous, uncompromising but satisfying listening prospect. Where Primum often worked towards textured heaviness, crushing your ears into willing submission by way of slow accumulation of layers, Alter is somewhat less formal, decked out in the sort of unashamedly bludgeoning, sledgehammer statement riffs to make Mastodon cry. Not to say Primum wasn't already heavy as fuck, but if that first half was the wild eyed stranger who coaxed you into the alley for a toke of his funny-looking cigarette, Alter is the point at which you realise you're smoking a neutron star."

"Despite its directness, this is still music that is entirely nuanced, always delivering new subtleties on repeated listens and always startling in its ability to plumb new depths of numbing heaviness. To put it bluntly there's a lot going on here at any given moment, and it's been engineered to digest over a long time."