(CNN) -- When it comes to the new "Teenage Mutant Ninja Turtles" movie, critics have found one begrudging silver lining: At least it's better than "Transformers."
Of course the live-action "Teenage Mutant Ninja Turtles," in theaters Friday, has some things in common with that toy-based franchise, beginning with its association with Michael Bay. The "Transformers" director served as a producer on 2014's "Turtles" adaptation -- leaving the directing to Jonathan Liebesman of "Battle Los Angeles" -- and tapped former "Transformers" star Megan Fox to go along for the ride.
In "Turtles," Fox plays April O'Neil, the eager NYC TV reporter who stumbles across the titular crew of teenage mutants who are well-versed in the martial arts. As April learns, this quad of wise-cracking reptiles, who have a fondness for pizza and a rat for a mentor, are the result of a lab experiment.
So there's the first sigh of relief for longtime fans of "turtle power": the new "Turtles" backstory is pretty faithful to the legacy of the comics, animated series and movies that came before it. There's a tweak involving April's childhood relationship to the turtles, but, overall, Donatello's still the brainy one; Raphael's still the hothead; Leonardo's still the leader; and Michelangelo is as party-ready as ever.
The problem, critics say, isn't that Bay, Liebesman and script writers Josh Appelbaum, Andre Nemec and Evan Daugherty didn't respect the lore, or that the movie doesn't deliver on action. It's that they revived the franchise with no sense of humor or affection, or even a clear understanding of their audience.
"The new adaptation," says the Los Angeles Times, "often feels like some sort of corporate seminar in brand management. There is something half-hearted about the entire film, as if those behind it were involved not because they wanted to make it, not because they should make it, but just because they could." It's not "out-and-out terrible," but it's not "particularly memorable," either.
Variety wound up in the same place of ambivalence, remarking in its review that "Teenage Mutant Ninja Turtles" is a "back-to-basics origin saga that is neither a particularly good movie nor the pop culture travesty that some were dreading."
There are all the usual Bay trademarks -- "chaotic action, crass side jokes, visual-effects overkill, Megan Fox" -- but on the other hand, it's also "nowhere near 'Transformers'-level off-putting," Variety shrugs.
For The A.V. Club, it isn't "fidelity" the movie lacks, "but a spirit of genuine boyish fun ... . 'Ninja Turtles' exists for the sole purpose of squeezing a few more drops of milk out of an old cash cow. At least the Turtles themselves look cool, strange new nostrils and all."
But according to The Washington Post, those turtles -- whether you find them to be cool or simply creepy -- don't get nearly enough screen time, and are treated more like "sidekicks to the actual focus of this film: summer-movie sexpot Megan Fox."
USA Today, which found the movie "charmless, dull and derivative," joined the party line and conceded that "while there's nothing particularly playful, fun or clever about this big-screen 'Turtles' re-boot, there is some good news ... the ninja turtles are more enjoyable to watch than 'Transformers.' "