What is wrong with action movies this year? Last year, when an action movie was dumb, it had the decency to make up for it with mind-blowing, bone-crunchingly awesome stunts and action sequences (cough, "The Raid: Redemption").

So far this year, though, all the big blockbuster action movies – like "A Good Day to Die Hard" and its slightly more tolerable cousin "Olympus Has Fallen" – act as though they have a license to kill brain cells. Worst of all, they only provide marginally diverting action to make up for it. Now there’s the long awaited "G.I. Joe: Retaliation," the most mind-numbing of the bunch.

And no, the 3-D conversion that delayed the film for almost a year does not make the proceedings any better.

"Retaliation" takes place a little while after the events of 2009’s "G.I. Joe: The Rise of Cobra," which ended with Cobra Commander and metal-head Destro captured, the president replaced by the shape-shifting Zartan (Arnold Vosloo), the Joes – led by Duke (Channing Tatum) – temporarily victorious. They apparently suffered several retirements, as most of the Joes from the last film (Rachel Nichols, Marlon Wayans, Adewale Akinnuoye-Agbaje) are nowhere to be found. Their toys must not have sold well.

Instead, newcomers Roadblock (The Rock), Lady Jaye (Adrianne Palicki) and Flint (D.J. Cotrona) join Duke and the masked ninja Snake Eyes (Ray Park). Considering how little character or personality they have, I’d just call them The Rock, Girl and Guy Who Isn’t The Rock. I hope you like following these bland future action figures, because they’re all we get after the devious fake president (Jonathan Pryce, one of the few cast members just having a good time) wipes out the Joes – including Duke.

That’s right; the rumors of bonus Tatum being added were wrong. He lasts about 15 minutes, shares a few forced but mildly diverting moments of male bonding with The Rock … and then gets vanquished.

Thus the stage is set for revenge, with the remaining Joes teaming up with the original G.I. Joe (Bruce Willis, either bored or exhausted from starring in his sixth movie in less than a year) to travel the globe to expose the fake president before he, Cobra Commander and new baddie Firefly (Ray Stevenson) take over the world with the help of their super mega death satellite – which, of course, comes with a self-destruct switch. Apparently the rest of the world leaders are in on the plan too, as they seem far too willing to send nuclear missiles flying willy-nilly across the globe with their shiny nuclear button suitcases.

Meanwhile, Snake Eyes and new character Jinx (Elodie Yung) are up in the mountains because if they weren’t, we wouldn’t be able to have a ninja wirefight on the side of a cliff. That’s as good a reason I can give you. There’s something about past ninja sins, a dead master, RZA and villain Storm Shadow (Byung-hun Lee) needing to fix his back, but it’s padding dedicated to non-characters that seem about as alive as plastic toys.

Writers Rhett Reese and Paul Wernick – the duo behind the actually quite clever zombie comedy "Zombieland" – load "G.I. Joe: Retaliation" with an excess of characters but a lack of anything fun or interesting for them to do or say. The Rock is locked onto glum revenge mode, and everyone else is just a vehicle for action, sloppy exposition or, if you’re Lady Jaye, sexy outfits. It’s a movie overstuffed with nothing.

Director Jon M. Chu tries to bring the movie to life with the action, and he almost manages to do it with some of the set piece moments, like the aforementioned mountainside ninja battle and a late gun-punch fight. At the same time, however, there’s just so little to care about or get attached to, both in terms of story and characters, that it falls as flat as one of the wire-fu ninjas with his rope cut. It’s hard to feel much is really at stake when even blowing up London causes little more than a shrug.

Then again, a shrug is all that "G.I. Joe: Retaliation" seems to be going for. Instead of dumb fun, the film is fully dedicated to dumb mediocrity and assumes that a few sequences of merely competent action will make up for neglecting everything else. That’s how you get a story in which the president can launch a doom satellite into space and seemingly replace the entire military with his personal goons without anyone noticing. Well, Lady Jaye does … when she notices his fingers folded differently and his use of the word "soda" instead of "pop."  

It’s a frustratingly joyless and charisma-free project, content to play down to the low expectations set by the previous film and the Hasbro logo at the beginning of the credits. This is normally around the time when I say that there’s enough explosions and fight scenes to satisfy undemanding fans, but when the final product is this devoid of substance, they should be demanding more.

Like the rest of this latest batch of action movies, "G.I. Joe: Retaliation" finds plenty of ways to blow stuff up. Now if only they could find a reason for audiences to care.