C-

This is the first 3-D movie from Jerry Bruckheimer, the last producer you’d think of whose pictures needed to be more in-your-face. It’s also Bruckheimer’s first children’s movie, which doesn’t stop it from ending with lots of explosions, hair’s-breadth escapes and high-tech razzmatazz. But though “G-Force” has all that, and furry animal stars to boot, it’s fatally lacking in charm and a real sense of fun.

The story, it should be noted, isn’t Bruckheimer’s; director Hoyt Yeatman reportedly got the idea for it from his young son, just as Robert Rodriguez was moved to do “The Adventures of Shark Boy and Lava Girl” by his kid’s fantasies. Which only proves that if you’re a filmmaker, it’s probably best not to rely on the tykes in your household for inspiration.

In a nutshell, the plot is that a bunch of guinea pigs—earnest leader Darwin (voiced by Sam Rockwell), goofy Blaster (Tracy Morgan) and sultry Juarez (Penelope Cruz), along with computer-savvy mole Speckles (Nicolas Cage)—have been trained as a team of secret FBI agents by likable scientist Ben (Zach Galifianakis) and his pretty assistant Marci (Kelli Garner). When they fail to uncover the goods about some plot supposedly being masterminded by electronics magnate Saber (Bill Nighy), Ben’s operation is summarily shuttered by an officious Bureau honcho (Will Arnett). That leads to the critters being forced into the larger world, where they meet a couple of new characters in a pet shop—another guinea pig, a big, lovable slob named Hurley (Jon Favreau), and a ferret called Bucky (Steve Buscemi). And the intrepid Darwin perseveres in his mission, which leads to a big melee on the grounds of Saber’s tightly-guarded mansion in which some “Transformers”-style effects are mixed with SWAT-style action and those myriad explosions.

Except for the replacement of cardboard human characters by computer-animated rodents, this isn’t all that far removed from the usual loud, chaotic Bruckheimer fare. And though the CGI is fine and the visuals might keep kids interested, there isn’t much in the way of wit or cleverness to engage them, and certainly not their parents and older siblings. The live-action human figures are dull as dishwater—Galifianakis seems to be sleep-walking his way through his scenes, and even the usually frenetic Arnett is becalmed. Nighy, to be sure, reprises the snide shtick he mastered in “Underworld,” though here without the makeup, but his turn is about as good as Mickey Rourke’s was as the mad plotter in the equally misguided “Alex Rider: Operation Stormbreaker,” in which a kid, rather than a guinea pig, assumed the agent duties.

That puts the onus on the critters, and their little shoulders prove inadequate to the task. They’re supposed to be cute, of course, but except for the wild Bucky, who’s blessed with Buscemi’s manic energy, they’re a pretty dull group. Darwin’s the worst offender, hobbled by Rockwell’s flat voice performance, but the others aren’t much better; when Blaster and Juarez—given a bit more energy by Morgan and Cruz—are adopted as pets by a couple of spoiled kids, for instance, one would expect big action sequences to follow, but their adventures prove surprisingly pallid. Favreau gives some panache to Hurley, but even there the result’s disappointing (did we really need the flatulence gags?) and the best that can be said of Cage’s Speckles is that the voice is unrecognizable. Not that his career, in its current state, would suffer much from any further embarrassment.

Of course, technically “G-Force” is first-rate. The CGI work is solid, and the 3-D effects bold and insistent. The regular footage is less impressive, with the production design (by Deborah Evans) and cinematography (Bojan Bazelli) that’s about what one expects of a medium-grade Disney live-action effort.

During a season when families are desperate for something to hold the attention of their youngsters for an hour or so, this picture will probably do some business; but a second or third trip to “Up” would be a lot more fulfilling. 3-D and Bruckheimer’s involvement apart, “G-Force” winds up resembling another mediocre Disney combo of live-action, special effects and secret agent goofiness from a decade ago (and one that also had a prominent “G” in the title)—“Inspector Gadget.” That should give you pause.