Film critics are not meant to talk about their own experience of watching a movie in terms of specifics - the venue, the dinner they had before, the phone call they had immediately after, the lumpy spot in the seat cushion. This is because film critics like to pretend to be oracles, whose opinion applies to all people at all times, and of course that's just not true at all. In the undying words of Robert Warshow, "A man goes to the movies. The critic must be honest enough to admit that he is that man." Unless he is a woman, but the quote is from the 1950s, so we can let that pass.

Here's why I'm bringing this up in a review of Rock of Ages, of all things. As it happens, I saw the film during my first trip to New York; I saw it in Manhattan, moreover, and not so very far long after nor far away from my first exposure to Times Square and the area around 42nd Street. Given who I am - the critic must be honest - "Times Square" and "42nd Street" conjure up a cultural memory of the grind houses and strip clubs and whores that once populated that region, and have sense been chased away and extinguished by tourist-coddling stores and shiny signs and a profound sense of packaged artifice. It felt to me like a northern enclave of Walt Disney World in the center of a major city; it felt even more like the equally surface-level, packaged theme park experience of Las Vegas. And since this was on my mind already, it wasn't hard to bring it into Rock of Ages itself, which is a story about the dying moments of the third of the great American sin pits, the Sunset Strip in Los Angeles during the late 1980s, with songs of that era sung by the characters in the movie as commentary on their lives, though it is not always the neatest fit.

And, like giant candy stores where there used to be grind houses and water slides where mafiosi used to break gamblers' knees, Rock of Ages takes something filthy and nasty and honest, and family-friendlies the shit out of it. This makes me sad, for even though the hair metal pose was just that - a marketing gimmick to make angry young white heterosexual males feel like they had somewhere to go where it was okay to indulge in their anti-social tendencies, at a certain price, naturellement - I have a guiltless affection for the genre, which I am well aware is not the correct opinion to have, but I long ago gave up even imagining that might be able to have hip taste in music. Therefore it is sorrowful to me, to see the music defanged and stripped of its ire and turned into a frolicking night of singin' and dancin' and hey! bring your grandma. For Rock of Ages is, after all, a product of that very same post-Giuliani NY theater district, and hot dog, I'm relieved I was able to bring it all full circle.

Taking place over a certain stretch of months in 1987 - exact chronology isn't the film's strong suit - this is the evergreen tale of a wide-eyed girl from Oklahoma, Sherrie (Julianne Hough), who comes to Los Angeles to make it as a singer; and the baby-faced city kid, Drew (Diego Boneta), who falls for her the second she walks into the bar where he works. And not just any bar! This is the legendary made-up club The Bourbon Room, beloved child of aging rocker Dennis Dupree (Alec Baldwin), and in its heyday in the '70s and earlier in the '80s, it was the place where all the great rock bands tested their mettle. I'd have written "tested their metal", which would have been a pun, except that I think most of you would assume I'd made a typo, and the rest wouldn't notice that it was wrong.

I was somewhere. Right, the Bourbon Room! Currently at the center of a plot by the gormless new mayor, Mike Whitmore (Bryan Cranston), who is being controlled by his mustache-twirling gorgon of a wife, Patricia (Catherine Zeta-Jones), to clean up the Strip by driving all the filthy rock clubs out of business. Oh God. It writes itself, doesn't it, and you all see where it's going: the savior of the day is going to be legendary, but currently strung-out and self-loathing Stacee Jaxx (Tom Cruise), whose oil spill of a manager, Paul Gill (Paul Giamatti) endeavors to steal all of the money that the Bourbon Room makes on Stacee's show, plunging them even nearer to financial collapse; he also steals Drew, promising to make him a rock star and forcing him to be a pathetically banal "rapper" in a boy band instead; Sherrie is stung by his betrayal and flies away to find fame though she ultimately can do no better than working at a strip club under the kindly - we might even say, "magical" - hand of Justice (Mary J. Blige), who has no story or personality of her own. Malin Akerman is on hand as the Rolling Stone reporter who represents Stacee's one chance at romantic and spiritual redemption, in a subplot that's about as convincing as putting a giant panda in tights and calling him Baryshnikov, while Russell Brand floats about as Dennis's second-in-command and is charged with saying lines that are all variations on, "Cor! Can yew b'lieve how bloody English Oi am? It's totally mental!" It takes 123 punishingly long minutes for this to play out, incidentally, and it seems really obvious from where I'm standing that there's a much better, cleaner 90-minute film that takes place on one night and hits most of the same points, but they didn't hire me to doctor the script.

It's tremendously predictable, but it is a musical, and a dash of predictability does sort of come with the territory. It's one of the things we love about the form, when it's done right. That is not the case here. Sure, if we're judging on the Mamma Mia! scale of basic cinematic competence, Rock of Ages is unabashedly and objectively the better jukebox musical: scenes are assembled coherently if not with the utmost clarity, and the actors have all generally been turned to point in the same direction, though Zeta-Jones and Cruise are by a criminally large margin the only people onscreen worth bothering with, largely because they are the only two who understand how to have much fun with what is, after all, a schlocky and disposable premise.

Yet "this is functional" is hopefully not the yardstick we want to use to judge films; "this is good" is better and "this is diverting and watchable" will do in a pinch. Watchable is the absolute peak Rock of Ages is able to reach; mostly it is at a static level of fairly dull adequacy where the most fun to be had is to daydream about how you might have staged a scene and done a better job of it than Adam Shankman, a choreographer-turned-director whose work is uniformly stiff and drab, except for his only full-on musical before now, 2007's Hairspray: no masterpiece, but a smooth enough experience marred just a little by some wobbly staging choices. There, it seemed odd that a choreographer would so willfully sabotage his own work by directing it in choppy, short bursts; here, it has become more of a problem and can only be called perverse. I adore Moulin Rouge! but it really did take a terrible toll on film musicals: the rapid-fire, experiential editing scheme that was so bold and perfect there has devoured all more disciplined, stately forms of cutting together dance routines, and that is why terrible things happen like an obviously fun routine set to "Hit Me with Your Best Shot", headlined by Zeta-Jones (who, we know from Chicago, is able to dance), is broken apart into such tiny constituent parts that it's frequently very exciting just to see the dancers complete one full motion of their arm in a single shot (it's also cross-cut with a sex scene in the dumbest way imaginable, but let's ignore that).

That same clunky, counter-intuitive, and above all else, un-entertaining mismanagement of the very thing we're meant to be enjoying - the musical numbers - is a constant companion. A lot of it is presumably from the source material, hence things like the apportioning of lines to far too many characters, turning solos into into quintets just so that Giamatti can sing one line of "Here I Go Again", or the gruesome, unsingable mash-up of e.g. "Jukebox Hero" and "I Love Rock and Roll", or, latter having no business being in a musical about hair metal to begin with. Some of it, though not very much, is the fault of the performers: mostly they are perfectly competent singers of easy songs, including those you would never have imagined singing (like Akerman) or would have preferred not to imagine (like Giamatti); there's some auto-tuning, but not enough that it destroys your ears. Julianne Hough's voice is a bit high-pitched and shrill and it gets supremely annoying as the movie go on, though I thought of how 20th Century Fox can save a lot of money on post-production sound editing by casting her as a voice in Alvin and the Chipmunks: Rodent It Be Nice.* But nobody fucks up the singing, even if most of them are not very good at the acting, and Hough and Boneta in particular look confused far more often than in love.

So no, the problem is mostly just that all the decent singing and decent dancing is rather more situated on screen than presented and framed for our delectation; it is a movie that puts all its chips on "have a dumb, fun time", and then mummifies all the fun bits beneath an awkward, inflexible, manic visual style. There's no real recovering from a musical that has only the music to offer, and then goes out of its way to sap the energy from all the numbers; it's what you call a generic requirement, and it's doubly important when the story and characters are as perfunctory as they are here. But! This part is important: when characters start to sing and dance, they don't have to enter a dream sequence first. So for all his clumsiness as a director, Adam Shankman still owns Rob Marshall. There's a comfortable though to cry yourself to sleep with when you get to wondering where all the good movie musicals went.