No longer can Arctic Monkeys be considered underdogs; given the notoriously fickle English music scene, perhaps that means they should be. Last year, the Sheffield quartet's Whatever People Say I Am, That's What I'm Not became the fastest-selling debut album in UK music history, spawning two #1 singles and winning the Mercury Prize. The band's early press clippings, like those for Gnarls Barkley, Lily Allen, and Clap Your Hands Say Yeah, highlighted their rapid netroots success story as much as their music, which is a traditionalist brew of observational storytelling, post-Libertines meat-and-potatoes guitar rock, and the heady enthusiasm of youth.

Fifteen months later, Arctic Monkeys' sophomore effort is already receiving a royal welcome at home, though the premature use of words like "comeback" underscores the precariousness of the group's situation. As for the Arctics, they've come back tougher, sharper, and bleaker, even if to non-fans of this brand of no-frills Britrock it probably still sounds pretty much the same. Favourite Worst Nightmare is in some ways better and in other ways worse than its breakthrough 2006 predecessor, but above all it's the assured statement of a self-conscious young band determined to deserve their acclaim. Eventually, maybe they will.

In interviews, singer and lyricist Alex Turner stays low-key about his abilities. "You never think, like, 'We're amazing, aren't we?'," the 21-year-old recently told Mojo. Nevertheless, Favourite Worst Nightmare flexes Arctic Monkeys' considerable songwriting and musical muscle with a confidence that sets the group apart from their UK rock peers; the latest songs seem to glimpse the possibility of greatness even when they fail to attain it. Turner finds new emotional depth on songs like breakup anthem "Do Me a Favour", which climbs patiently from baggy drums to a searing, guitar-led crescendo. Gradually shifting from the man's perspective to the woman's, he concludes, "How to tear apart the ties that bind?/ Perhaps 'fuck off' might be too kind," his raggedly bereaved croon adding Damon Albarn to the list of plausible vocal comparisons alongside Morrissey and Noel Gallagher. Similarly, the drum-less and bass-less "Only One Who Knows" is another big step forward for the band, taking a more deliberate, atmospheric view of a dying relationship: "They made it far too easy to believe/ That true romance can't be achieved these days."

If such heartache is a fresh addition to Turner's songs, so too, it seems, is the feeling that makes the pain possible. Real affection glimmered through the bickering on the debut's "Mardy Bum", but the girls on that album are mostly fake-tanned participants in meat-market mating rituals ("I Bet You Look Good on the Dancefloor", "Still Take You Home"). By contrast, Favourite Worst Nightmare unveils one of Turner's first proper love songs: The closing "505", draped with an apparent Ennio Morricone organ sample, poignantly if none too adventurously describes Turner's longing to get back to a hotel room where his lover awaits. "I'm always just about to go and spoil the surprise/ Take my hands off of your eyes too soon," Turner admits, displaying his usual gift for vivid imagery.

However, some of Favourite Worst Nightmare continues in the unfortunate direction of last year's Who the Fuck Are Arctic Monkeys EP, which found the band coming unappealingly to grips with fame. Turner's obsession with poseurs has always been the least likeable thing about his lyrics, but songs like "Fake Tales of San Francisco" at least reflected a nagging desire not just to repel phonies but to crave something true and real; here, with the band's debut certified as the "fifth greatest British album ever" by the NME, Turner's unrelenting bitterness makes him sound like one of the petty fakes he despises. It doesn't help that first single "Brianstorm"-- ostensibly about a T-shirt- and tie-wearing industry creep the band met in Japan-- shows the Arctics at their least melodic, swapping out the Supergrass "Richard III" riff that opened the debut and replacing it with pummeling, double-speed aggression. "Teddy Picker" heaps scorn on "professional pretenders," comparing the music industry to the toy crane machines in arcades, and mocking kids who "dream of making it, whatever that means". Check the mirror, dude, though Turner also squeezes in what sounds like a pointed jab at the music press: "When did your lists replace the twist and turn?" Fair play; the twist and turn here is, indeed, fab.

Favourite Worst Nightmare flirts, too, with the notion of the Arctics as an indie-dance group, enlisting the guidance of Simian Mobile Disco's James Ford (who also produced the recent debut album by Klaxons). The throttling playing of drummer Matt Helders has been a big part of Arctic Monkeys' appeal since the beginning, so the differences here are subtle: A thick bass groove on the Dr. Suessian "This House Is a Circus" ("berzerkus"?), four-on-the-floor beat on the Wizard of Oz-steeped "nostalgia" critique "Old Yellow Bricks", or repetitive fuzz-tone guitar jerkiness on fast-paced "If You Were There, Beware". While Ford coaxes commanding performances from the band, he modifies their trad-rock trajectory only slightly; Arctic Monkeys and Klaxons were never as different as the UK press suggested.

If Favourite Worst Nightmare is notably lacking something, it's another song like the debut's standout, "A Certain Romance". Arctic Monkeys have now traveled the world, and their new material veers from such detail-rich tales of growing up in provincial England, at times focusing instead on subject matter Blur pursued with sharper wit (and only slightly sharper hooks) on The Great Escape. "Fluorescent Adolescent", the current album's most obvious hit, shares a festival-ready ska rhythm with the debut's "Mardy Bum" (which shares it with Sublime's "Santeria"), but the new song describes something Turner can hardly know much about: a middle-aged woman's dreary sex life. "You used to get it in your fishnets/ Now you only get it in your night dress," Turner cleverly sympathizes. Sure, Arctic Monkeys may no longer belong to their old world of kids wearing "knackered Converse", drinking underage, and getting accosted by bouncers, but they're still too boldly tuneful not to find yourself rooting for them.