It’s almost impossible to fully encapsulate the meaning or ramifications of Green Day’s 1994 breakout mega-smash Dookie. It was the album that brought ’90s pop-punk out of the underground and onto the radio, giving new life to a rock scene then-choking on fading alt-rockers past their creative primes, with the album eventually selling more than 20 million copies worldwide.

So of course for the sequel to Dookie, Green Day—who at least back then were way punker than most gave them credit for—did the only thing three self-respecting punks could do in that situation: write a harder, darker, faster album fueled by sonic piss and vinegar. That album was Insomniac, the band’s fourth full-length release, which turns 20 this month.

From the moment drummer Tré Cool’s rolling toms gave way to the opening crunch of “Armatage Shanks,” it was immediately obvious Insomniac wasn’t going to be some sugary radio concoction crafted by recently famous mall punks looking to keep the gravy train rolling. There’s an anger and an urgency to singer-guitarist Billie Joe Armstrong’s nearly undecipherable vocals on that first track which sets a clear tone for what follows; the album’s remaining 13 cuts blast by from there, with only two tracks (“Brain Stew” and “Panic Song”) barely breaking the three-minute mark.

It’s also the last old-school Green Day album in the catalog; its successor, 1997’s Nimrod, began the band’s gradual transition into the broader, less genre-specific entity the trio fully embraced on 2000's Warning and then mastered with 2004’s American Idiot. On Insomniac, however, you still hear snippets of the Lookout!-era Green Day, like the Kerplunk-esque verses to “86,” as well as many of the qualities that made Dookie such a gargantuan hit. (For example “Stuck With Me” could easily be mistaken for Dookie’s “Sassafrass Roots.”). Insomniac’s emphasis on razor-sharp guitar riffs and addicting lyrical hooks very much carry on that Dookie tradition, yet with even more bite.

Topically, on Insomniac Armstrong didn’t let his newfound fame and suddenly ample cash get the best of him. His lyrics on the record project the same neurotic, disenfranchised, low self-esteem outsider who penned “Basket Case” and called himself “a loser and a user” in “When I Come Around.” Take “Armatage Shanks,” for example, with Armstrong stating, “I must insist on being a pessimist. I’m a loner in a catastrophic mind,” and later in the song calling himself a “self-loathing freak and introverted deviate.” Clearly, Armstrong wasn’t believing his own press.

His songwriting focus was no less biting in the third-person, either. One of the record’s key singles, “Geek Stink Breath,” was penned about his and his friends’ struggles with methamphetamine use and its lethal effects on the body (a topic he revisits again on “Brain Stew,” when he attributes his insomnia to being “f----d up and spun-out in my room”). Then on “Panic Song,” Armstrong delves into bassist Mike Dirnt’s panic attacks, explaining, “There’s a plague inside of me, eating at my disposition. Nothing’s left.” Armstrong offers a final twisted tale toward Insomniac’s end with “Tight Wad Hill,” (which was originally supposed to be the album’s title): A reference to Charter Hill near U.C. Berkeley, the song speaks of an unnamed male junkie, “begging for another fix / turning tricks for speedballs.” If Green Day were spending their platinum-record royalties on private jets and copious bling, it sure as hell wasn’t reflected in Insomniac’s gutter-raw lyrical imagery.

As is often the case in such instances, response to Insomniac was mixed at best. Green Day diehards adored the record for its tenacity and overt punk focus, but many of the millions of new fans who’d recently jumped aboard the bandwagon in the wake of Dookie were left somewhat scratching their heads. Though the album peaked at No. 2 and was double-platinum by 1996, it was obvious Insomniac wasn’t going to rack up the incredible sales of its predecessor. Critics, meanwhile, were positive but guarded in their assessments, praising the band for the album’s unflinching execution, but also noting a lack of growth from Dookie, save for the album’s heavier bent. For example, Entertainment Weekly wrote: “The few hints of growth are fairly microscopic: a tougher metallic edge to a few of the songs... and lyrics that are bleaker than Dookie’s.”

Those critics would get their wish with Nimrod, the follow-up to Insomniac, which began Green Day’s eventual transformation into the mainstream rock megastars we know today. But for anyone still hungry for the Green Day of old, Insomniac delivered in spades. It was stunning proof that for an artist, sometimes anger and vitriol are the most productive responses to success.

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