In A Star is Born, Bradley Cooper and Lady Gaga meet cute in a drag bar. Her character, Ally, is the rare biologically female performer allowed to sing there, and she’s belting out a classic Edith Piaf song. His character, Jackson, is a rock star who just finished a gig, and spotted the nearest neon sign that carried the promise of alcohol. She’s leaned over on her back to serenade the customer next to him, and turns and locks eyes with him. He’s smitten, both by the voice and the woman herself.

They and the movie stay in this smitten state for about the next 45 minutes, as a meet cute morphs into an unexpected evening, and then a couple delirious weeks in which she joins him on tour after he discovers that she’s not only a singer, but a songwriter. He forces her up on stage to sing the song she gave him bits of while they were sitting in a grocery store car park, a bag of frozen peas reducing the swelling on her knuckles after she punched a patron in another bar who tried to drunkenly leech off his stardom.

If only the movie – if only life – could stay suspended in such romantic highs. A Star is Born, which originated with a 1937 William Wellman film, has not been remade for the third time because it’s the story of musicians at opposite ends of their respective careers who join up and live happily ever after. And as their lives pass that crescendo and sink toward the type of turmoil that consumes them, the movie also loses that touch of magic that makes its first hour such an overwhelming delight.

But man, that first hour. In it we’re introduced to not one star, but two. If we didn’t know Lady Gaga could act like this, we also didn’t know Bradley Cooper could direct like this. It’s not her first time in the role of actor, though it is her first star vehicle. This is the first directing gig for Cooper, the long-time actor.

Let’s start with Gaga. Much is made of how she is not conventionally attractive, or possibly not attractive at all, though the rock star Jackson Maine begs to differ. Her appearance may be a matter of subjective opinion, but what’s indisputable is that she has one of the most interesting on-screen faces to look at in some time. It’s composed of a lot of sharp angles, from her nose to her eyebrows and everything in between, and Gaga uses them like an artist might use paint brushes.

One of the chief joys of A Star is Born is just exploring her face as she takes in all the strange and (initially) wonderful things that are happening to her. A struggling blue collar service worker who is trained to call bullshit on people, Ally looks at Jackson as though trying to assess whether this is all some elaborate practical joke. She’s looking through his face into his soul, always seeming to say “I’m vulnerable, so don’t say these things to me unless you mean them.” She’s tough and she’s got her defences up, but she’s also the little girl with dreams of stardom who wants to be told she’s good enough. It’s a magnificent, natural performance bursting with charm.

Cooper’s filmmaking lifts her up into the stratosphere. He sets up his camera at a perfect middle distance from his characters, shooting the live music performances as a master of concert documentaries like Martin Scorsese might. His camera swirls around its subjects, scooping them up in an intimate embrace, while also taking in the massive scale of these sold-out musical venues. He brings the same approach to the off-stage moments between them.

The film’s opening hour is a master class on showing, not telling. We know Jackson is an alcoholic not because someone sits him down and tells him he needs to check himself before he wrecks himself, but because of a furtive swig from a bottle of whiskey in his limousine after a gig. That could be anyone unwinding after a performance, but we suspect it’s not. For now though, this is all we need to know. We also know Ally is struggling in her high-end server job not because of a series of indignities she suffers, but just because it’s her turn to throw the rubbish in the bin outside the restaurant, and she can’t leave until she’s done so.

The narrative during this time flows forward on its own momentum, as we feel like we are meeting and getting to know these characters without some awkward third party having to step in to tell us about them. We experience their night and the following weeks as they experience it, as an illogical ride that they don’t want to get off. And it’s a hell of a ride.

All rides must end. Ally’s birth as a star has inarguably positive results for a woman who is on the verge of being fired from her day job; for a budding artist whose purest incarnation comes in impromptu showcases on stage with rock legends, it’s a bad sign. Enter the stock character of the evil British record producer, who can give Ally everything she thinks she wants, but in return will take her soul and the thing that makes her her. And that alcoholism thing for Jackson? It’s not getting any better.

If you are following the same story as the other three Star is Borns, you can’t give us a movie that’s a good time from beginning to end. And though it’s probably intellectually immature to want this ride to keep going, Cooper and Gaga have treated us to something so wonderful that the second half of this movie can’t help but feel like a letdown. As the movie runs 136 minutes, we have a lot of time to ponder the ways fame and success can go wrong, even and perhaps especially when they seem like they’re going right.

So if A Star is Born is something less than a total success, which it is, it’s probably because life is something less than a total success, and frequently goes places that disappoint us. It’s a useful lesson, but the medicine doesn’t taste particularly good.