There might, one supposes, be a Heavy Concept behind the title of this four-track, 17-minute EP by Chicago extreme metal band Nachtmystium, but the fact that, y'know, the words just sound cool is probably enough. However, their album from last year, the acclaimed Assassins: Black Meddle, Part 1, worked on at least three levels: 'metal' with an American accent (which serves as a decent description of Nachtmystium, in a way); a reference to Pink Floyd, whose influence came to the fore here and telegraphed the band's intention to avoid the pigeonholing of black metal puritans; and, according to singer/guitarist Blake Judd, describes their love of upsetting metal community applecarts by shifting styles from release to release. To suggest that Nachtmystium aren't the band they used to be would be to make Nachtmystium's day.

Doomsday Derelicts was recorded last year (just before Assassins' release, lest anyone think the content herein is an olive branch to mildly disgruntled longterm fans) in the audiophilic confines of Steve Albini's Chicago studio, Electrical Audio - read up on those Mexican bricks and Russian microphones and weep, gear freaks. Sanford Parker, also based in Chicago and commonly found recording doom, sludge and 'post-metal' bands, manned the controls alongside the band's own Blake Judd. It's a combination to make a certain type of rock enthusiast drool - just not a black metal fan, necessarily. It works a treat, though, much as Parker's recording of Assassins in his own studio opened up the quartet's psychedelic third eye.

'Bones' (as in 'making no', possibly), the first track, is pretty easy to read as a statement of intent. Equipped with a turbocharged and vaguely Motörhead-y bassline - Lemmy on speed, you say? Oh WAIT - a bass drum having the absolute monomaniacal shit beaten out of it, and a solemn church bell, it lasts less than three minutes and is the sort of punk-charred black metal that, while perhaps most closely associated with bands like Bone Awl, Ildjarn and more recent Darkthrone, could also slot into the mid-period Nachtmystium of Demise. Clearly, their crib hasn't had a full-scale Afghan rug/Zappa-on-the-crapper poster 70s stoner makeover. Track two 'Life Of Fire', conversely, has a skyward-tilted wigginess to it that suggests it could be a leftover from Assassins, as such, it's a wholly worthy exercise, but the EP's least interesting song.

Not previously a band who seemed keen to pen 'anthems', Nachtmystium may usher in something of a communal singalong at future shows with 'Hellish Overdose'. Casting the members as a remorseless, marauding army who annex territory with filthy force ("Spent last night in the gutter / Like the night before"), the notion of a blackened take on Manowar isn't the largest leap ever envisages, but hey, it works. "Can't get enough / Or even close / We never stop / Hellish overdose." A positively Priestian guitar solo plants a flag atop an edifice which is pretty much a definitive example of the 'black'n'roll' microgenre. Whereupon Nachtmystium clock, and then erase, your rictus grin with 'Pitch Black Cadence', a creepy, claustrophobic rumble with soloing that would sound at home on a Comets On Fire record.

Blake Judd and his bandmates clearly take an active interest in the public image of Nachtmystium, and harbour a determination that no-one should second-guess their intentions and career arcs. If this means that they're going to switch their game up every time they put a record out, and the records are as fresh and praiseworthy as Doomsday Derelicts, then may they be always obstinate and obtuse.