For anybody who’s spent much time on dance floors in the last 20 years, the first few bars of Underworld’s “Born Slippy” are a portal. They take a person back to their younger self, a more reckless self. As the top commenter on the track over on YouTube recalls, “This make me remember this one time when i robbed my m8s in london,they were slepping and i took the bag and run away. Crazzy times.” The past, as they say, is a foreign country.

But if we can’t go back, the film industry insists, we can make sequels with slightly overlapping soundtracks. Twenty-one years after the original’s release, T2 Trainspotting hits America this March, and is already out in the U.K. The core cast is the same as the old one, minus the sweet character of Tommy MacKenzie (played by Kevin McKidd, aka Dr. Hunt from Grey’s Anatomy). As you’ll remember, Tommy’s the one who originally isn’t on heroin, but contracts HIV and eventually dies of toxoplasmosis after neglecting a kitten.

Rumors of a follow-up to Trainspotting have hummed for a long time, with most assuming that director Danny Boyle would return to adapt author Irvine Welsh’s novel Porno (2002). Boyle is now a megastar, with movies like 28 Days Later, Sunshine, and Slumdog Millionaire behind him, and Welsh is a bit of a loose cannon who gives too many interviews. So nothing was guaranteed. At the 2015 Telluride Festival, Boyle finally announced that a sequel was, indeed, in the works. The film is not a strict adaptation of Porno, but it is close: that book also returns to Trainspotting’s main characters after a long gap.

In this sequel, Mark “Rent Boy” Renton (Ewan McGregor) returns to Edinburgh after disappearing to Amsterdam twenty years prior with a bag full of his mates’ money. He gets back in touch with Simon “Sick Boy” Williamson (Jonny Lee Miller), who has inherited a pub and convinced himself that a beautiful young sex worker is his girlfriend. He also finds his old friend Spud (Ewen Bremner), and tries to help him kick heroin. Spud had the best line in the first movie, I think, at a job interview:

Interviewer: Mr. Murphy, what attracts you to the leisure industry?

Spud: In a word: pleasure. It’s like, my pleasure in other people’s leisure.

Meanwhile, Begbie (Robert Carlyle) has been in jail. But now he’s out, and he very much wants to kill Renton.

Trainspotting may have been the defining movie of the 1990s, if we can agree that heroin was that decade’s theme. Kate Moss, Nirvana, Blur, Rent Boy: druggie sybarites the lot of them, and they are cultural products of a piece. But these are different times. Why make a sequel now?

Begbie and Sick Boy in the original Trainspotting (1996).

I managed to catch the movie in London, where I grew up. Walking to the cinema, I only had to look around me to see why T2 Trainspotting is timely. Everywhere, skinny white boys in filthy drainpipes and bomber jackets answered my question. The light bounced off their shaven heads as they slung arms around their bony girlfriends, who all had center-parted bobs. My brother had the original Trainspotting poster up on his wall when we were younger. I thought those characters looked the absolute zenith of style and maturity. Now I look at these teenagers and want to pat them on the head.

Spud gets the best lines again. In one of the movie’s first scenes, he loses his job because he’s been so high on smack for so many years that he’s never learned that the clocks go back in the summer. Later, he starts to write up his memories of the Trainspotting era. Irvine Welsh himself has a cameo as a fence. Mark repeatedly gets himself out of scrapes with his superior cardiovascular abilities, honed by his exercise addiction. At the gym, he always wears Trainspotting-orange. Kelly MacDonald—who plays Diane, Rent Boy’s underage love interest in the original—is in the movie, but only for about one minute, fully clothed.

The best scene in the sequel is a two-second shot of Spud dropping a bunch of legal pads while trying to walk down the street. The second-best is a fight scene between Mark and Simon, in which the latter briefly waterboards his opponent with an Irn-Bru tap from behind the bar.

The plot is tight, and Bremner and Carlyle give sterling performances. T2 Trainspotting is very watchable. But in the end Ewan McGregor’s face is just too familiar. It hasn’t seemed to change for a long time now: He looks and sounds like himself, not Mark Renton. That’s the danger of a personal brand. When Mark dances to “Lust for Life” in his bedroom, he looks like Ewan McGregor on a talk show re-enacting a scene from long ago. When he updates his famous “choose life” speech to namecheck Instagram and revenge porn, it just feels silly.

You’d forgive any of these flaws if the soundtrack had lived up to the old one. But the new version of “Born Slippy” is called “Slow Slippy,” and its beat never drops. Instead, it sort of bleats plaintively over the sad bits, taunting you with memories of your own youth. Any Trainspotting fan ought to see this sequel, but look not for the exhilarating exhortation to anarchy you remember from the old one. Simon accuses Mark of being a “tourist” in his “own youth.” It’ll feel that way to you, too, and nothing hurts more than nostalgia. If you’re prone to that particular emotion, T2 Trainspotting is going to hit you like a pint glass flung carelessly backward off a pub balcony: hard.