Alloy Oops: Transformers is the make and model of a dull movie.

There’s a Herbie the Love Bug moment in Transformers. A high-school kid just got his first car. He’s crushing on a girl who looks 10 years older than he is and doesn’t tax her taut body by throwing on a lot of clothes. She needs a ride home; the vehicle flings its passenger door open and plays the Cars’ “Drive.” Once it’s got her inside, it further helps out its owner by motoring them to a remote spot—and switching the radio to “Sexual Healing.”

OK, so maybe it’s a scene that would make Herbie blush. But what do you expect from a movie based on…toys? Transformers is the latest directorial effort from Michael Bay, so you probably don’t need the PG-13 rating to tell you that despite its Hasbro origins, the movie’s not for the little ones. But unlike the rest of this summer’s something-for-most-of-the-­family fare—particularly other fanboy stuff like Spider-Man 3—the live-action Transformers has an unflattering vibe all its own: It’s not for kids, but it’s not quite for geeked-out adults, either. It’s for the stunted.

Bay and his screenwriters, Mission: Impossible III duo Roberto Orci and Alex Kurtzman, are betting that audiences will feel that a heap of CGI sophistication will make up for lack of depth elsewhere. (And they’re probably right, alas.) The story is a gibberish-laden shell that integrates the giant robots from another planet, who until now have been kept there in the animated TV series and 1986’s The Transformers: The Movie. Shia LaBeouf trains for his upcoming Indiana Jones role as Sam, the uncool student who ends up with the prying old Camaro that he eventually learns is Bumblebee—though Bumblebee was originally a Volkswagen Beetle—one of the good-guy Autobots. It (he?) and a few other bots are there to support their leader, Optimus Prime (Peter Cullen), as Optimus travels to Earth and hunts for the Allspark, something that’s ridiculously important for the Autobots to have.

Of course, the evil Decepticons also want it. And they almost had it: Megatron (Hugo Weaving), the baddest of the bad, came searching for the Allspark back in the 19th century, only to accidentally freeze and later be discovered by Sam’s great-great-grandfather, an explorer. Before he was paralyzed, though, Megatron etched out a map to the Allspark on Grandpa’s glasses, which are currently in Sam’s possession. Why did the Autobots wait until 2007 to gain control of the Allspark? Apparently it took that long for the Decepticons to figure out how to hack the government’s security system (and, uh, attack U.S. soldiers in the Middle East) and defrost Megatron—or something like that.

All you really need to know, though, is that the shape-shifting androids are in a battle of good vs. evil, and it’s just an excuse for a lot of explosions, gunfire, childish humor, and a couple of completely unnecessary hot women. (How important are the actresses’ looks compared to the movie’s logic? Sam’s love interest, played by Megan Fox, somehow gets a wardrobe change while everyone else is knee-deep in Armageddon.) The action is mind-numbing rather than stupidly invigorating, filmed primarily in Bay’s messy style of thrashing cameras and dizzying edits. What Bay and his technical crew do get right, on the other hand, is what most of the audience members probably came to see: the alien stars morphing from their disguises as helicopters, trucks—whatever each stealth situation calls for—into their badass (or goodass) robot selves. From machine to ’droid and back again, their transformations are quick and fluid, often seamlessly occurring midair. The bombs may not impress you, but at least this will.

If only the script weren’t unbearable. Despite a 144-­minute running time, the story gets choppy. (Days turn instantly into nights, while lines such as “I had fun” refer to nothing we’re privy to.) The characters are one-note: Sam’s immediately comfortable with his new world, rattling off details of the planet’s possible doom to others; Fox’s Mikaela is a function of her wardrobe. And the jokes are painfully adolescent. (Ha ha, that robot is peeing—­something—on a government official! That guy’s picking his nose!) The package would be passable for kids—if they were the movie’s intended audience. But our inner children deserve better.