When I was a kid, a toy was just a toy. G.I. Joe never turned into a jeep or a rifle; he just remained G.I. Joe. Although I was in college for the initial wave of Transformers, I get the appeal. A fierce-looking robot can twist and fold into, say, a truck, so a Transformer combines the “playability” of toy vehicle, action figure and Rubik’s Cube. That’s three playthings in one toy.

As a commercial property, the Hasbro line showed its facility for change. It transformed into a TV cartoon with a complicated backstory. The new film version proves the Transformers can morph into a live action motion picture, although director Michael Bay can be at once the franchise’s greatest champion and worst nemesis. To borrow the Transformers’ terminology, the Pearl Harbor and Armageddon director ultimately falls on the side of the righteous Autobots rather than the nefarious Decepticons, but it’s a pitched struggle.

Masquerading as tanks, helicopters, etc., rival factions of alien robots search Earth for the Allspark, a supposedly all-powerful cube. The flesh-and-blood side of the story, scripted by Roberto Orci and Alex Kurtzman, seems already overrun by androids. As a high school hottie with mechanical aptitude, Megan Fox comes across as a Hollywood sex-bot right off the assembly line.  Anthony Anderson’s gluttonous, excitable hacker? Jokebot.  Jon Voight’s no-nonsense secretary of defense?  Authority-figure-bot.

Shia LaBeouf provides nearly the sole human touch as hapless high schooler Sam Witwicky. To raise money for his first car, Sam plans to sell a family artifact that may provide the location of the Allspark. He ends up with a beat-up Chevy Camaro that seems strangely eager to be purchased. Transformers’ first act draws on elements of Herbie and Christine, with the car radio prompting romantic cues such as “Sexual Healing” and, later, pursuing him with no driver.

Transformers stands out in an era of celebrity voices by casting many of the original speakers from the old cartoons. Without irony, Peter Cullen gives Optimus Prime a seriousness that suits the role’s status as a would-be icon, although it’s hard not to laugh at a declaration such as, “Autobots, let’s roll!”

Transformers even includes an extended slapstick scene that comes across as the film’s attempt to “humanize” the giant alien robots. Although the humor clunks, you can appreciate the attempt to distinguish the Autobots from the Decepticons. They’re better at using their zillions of moving parts to strike action-hero poses.

It’s a little odd that Transformers features US troops in the Middle East and builds to a climax rife with urban destruction without ever echoing the war in Iraq or 9/11. It features some fuzzy political satire about government secrecy, with John Turturro, as a “Men in Black” type, acting like he’s in an update of Dr. Strangelove. More often it’s a love letter to the American military, celebrating hardware with a zeal worthy of Top Gun. With a defense secretary as a hero and not a whiff of present-day subtext, Transformers is a film Donald Rumsfeld could love.

Overall, though, the essential purpose of Transformers isn’t to develop rich characters or pointed themes; it’s to show huge machines smashing each other and their surroundings. By the spectacular standards of fireworks displays, kick-ass rock concerts and demolition derbies, Transformers delivers.

The imposing early scenes give the film a sense of menace and scale absent from the American Godzilla from 1998. Early on, a deceptive “helicopter” ambushes an American base in Qatar and, later, Josh Duhamel’s stalwart soldier leads his troops in a battle with an oversized, weaponized techno-scorpion.

By the time the Autobots and Decepticons race down busy highways and square off in a crowded city, Bay constructs propulsive set pieces and thrilling images, such as Optimus Prime and his archenemy Megatron leaping through a skyscraper, smashing through the floors and erupting from the other side.

For all its pandering comedy and flat characterizations, Transformers offers sights you’ve never seen in a movie before—which should be the minimum standard of a would-be summer blockbuster. It’s undeniably fun to watch Bay play with the most expensive toys on the planet.

TRANSFORMERS * * 1/2

Directed by Michael Bay • Starring Shia LaBeouf and Megan Fox • PG-13 • 144 min • At the Century Cinemas Del Monte Center, Maya Cinemas, Northridge Cinemas.