Sometimes, it’s best not to revisit the past. That’s the thesis behind T2 Trainspotting, but it’s also the challenge with which this movie consistently grapples. Checking back in on the characters from the 1996 original, the new film self-consciously questions its own existence, proving just satisfying enough by being as unromantic as its predecessor—albeit in very different ways. The first Trainspotting was about the horror of heroin, while T2 argues that nostalgia is just as addictive a proposition—and just as toxic.

Released in the summer of ‘96, Trainspotting was a snot-nosed, zeitgeist-seeking dark comedy. Revisiting it recently, I was reminded that while we were meant to find the antics of Mark Renton (Ewan McGregor) and his degenerate buds funny, director Danny Boyle never fully disguised his antipathy for these cretins. With its flashy soundtrack and buzz factor—the movie was based on Irvine Welsh’s white-hot novel—Trainspotting felt like the U.K.’s answer to Goodfellas and Pulp Fiction. Understandably, some audiences were so swept away by Boyle’s cinematic rush that they failed to notice what utter losers these guys were—and how pathetic their so-called rebellion from polite society turned out to be.

T2 drags and meanders, but Boyle hasn’t lost sight of that core theme—if anything, his new film amplifies it. Reuniting with Trainspotting screenwriter John Hodge, who based his script on Welsh’s novel and its follow-up, Porno, Boyle has no illusions that, decades later, these Scottish misfits will be any wiser or more mature. They’re simply older—and, quite often, not any better off.

The film starts with Renton returning to Edinburgh for the first time since Trainspotting’s finale, where he betrayed his mates, taking their drug money and hightailing it out of town. Stung by guilt, he decides to find out what happened to his friends, not being terribly surprised that Spud (Ewen Bremner) remains ravaged by heroin addiction, contemplating suicide. Meanwhile, Sick Boy (Jonny Lee Miller), now heavily into cocaine, has dreams of starting a brothel, raising money for it by blackmailing upstanding members of society who are lured into having sex with his Bulgarian prostitute girlfriend Veronika (Anjela Nedyalkova). The reunion between Renton and Sick Boy is a tense one, but they decide to mend fences once Renton admits that the real reason he’s home is because he’s about to lose his job and his wife. At 46, he discovers he doesn’t have anything he can call his own.

On the list of reasons to justify a sequel, having your main character forge a fragile truce with his former best friend to start a high-class whorehouse is not among the most compelling, and T2 often struggles to make its protagonists’ motivations believable. But what mostly saves the film is that Boyle anticipates the audience’s skepticism and embeds it into the proceedings. All sequels are exercises in nostalgia, and everything from Back to the Future Part II to 22 Jump Street has satirized and commented on the tendency to repeat what was once successful while pretending it’s something new. But T2 goes a step further, critiquing its characters’ bizarre fondness for glorifying the past. In the process, the entire sequel becomes a subtle shaming of how far they haven’t progressed since the last film. The great tragedy of Renton and his chums’ lives isn’t that they’re middle-aged—it’s that they’re pining for their junkie youth.

At first, Renton seems the furthest removed, both geographically and emotionally, from his 20s, looking far fitter and centered than the smart-ass we met in Trainspotting. (It also doesn’t hurt that McGregor, who was still an upstart in 1996, now feels every inch the relaxed, commanding movie star.) But once his seemingly posh adult life goes pear-shaped, it’s almost pitiful how quickly he reverts to old ways. Renton has sworn off drugs—his one act of genuine generosity in T2 is to help Spud kick smack—but the small-minded, chip-on-his-shoulder attitude that provoked the addiction in the first place remains depressingly in evidence.

Attracted to Veronika—and more than happy to steal her away from Sick Boy—Renton still clings to the underdog rebelliousness that he thinks once made him a blazing original. Explaining to Veronika about his friends’ “Choose Life” inside joke—which inspired Trainspotting’s snarling opening monologue—he’s at first almost embarrassed. But as he accesses those old anarchic feelings, we see the youthful fire and, also, the hotheaded stupidity.

He’s not alone in longing for a scarred past. Spud finally beats drugs, but it provokes him to become obsessed with anecdotes from that earlier time, compulsively writing them down as a way to ensure they live on forever. Sick Boy clearly has not really forgiven Renton, holding onto that anger like a badge of honor, but when they begin to reminisce about the good ol’ days, Veronika couldn’t be more bored: They’re overgrown boys who emotionally remain stuck in the ‘90s.

Boyle doesn’t spare the audience in this critique, tormenting viewers’ expectations by reprising three of Trainspotting’s most indelible songs—Iggy Pop’s “Lust for Life,” Lou Reed’s “Perfect Day,” and Underworld’s “Born Slippy”—but offering them in remixed, condensed, or cover versions. It’s an obvious point, but Boyle gives it weight: Maybe, like the characters, fans of the original film will want to savor this trip down memory lane, but the experience won’t be exactly the same. How can it? Too much time has passed—for them on the screen and for us watching.

The final member of the old gang propels T2’s eventual conflict: The thickly accented, psychopathic Franco (Robert Carlyle) has just escaped from prison and wants bloody revenge on Renton. Before he tracks down his old companion, though, Franco, too, will try to recapture the past, discovering that his grown son wants nothing to do with this two-bit criminal. Ironically, the drug-free Franco was actually the relatively wise one in Trainspotting, warning the rest of his mates about heroin’s destructive power, but his brawling anger and inability to accept that the world has changed since he’s been incarcerated makes him as hobbled as everyone else in T2.

Does that include Boyle? Trainspotting was his second movie and a showy breakthrough after his Hitchcock-ian 1995 debut Shallow Grave, which also starred McGregor. Since then, the director has gone on to be a respected industry figure, his Slumdog Millionaire winning eight Oscars, including Best Picture. But there’s always been a bit of the showoff to him—especially in recent films like Trance and Steve Jobs, in which the audacity of the imagery sometimes outpaced the ideas. T2 is a kaleidoscope of clever visual tricks—spot-on allusions to Raging Bull, myriad callbacks to specific shots from Trainspotting—that demonstrates that Boyle remains a master of kinetic busyness.

But that showmanship is ultimately at the service of something quite sobering. For all its surface flash, T2 is the continuing story of some marginally interesting screw-ups who are probably never going to get their act together. This sequel’s great insight and limitation is its suggestion that these losers don’t deserve anything more than a movie that’s a shadow of its predecessor.

Grade: B-

Grierson & Leitch write about the movies regularly for the New Republic and host a podcast on film, Grierson & Leitch. Follow them on Twitter @griersonleitch or visit their site griersonleitch.com.