While still among the producers, del Toro has passed the directing reins to Steven S. DeKnight, a veteran TV producer ("Daredevil," "Spartacus") making his feature debut. The most notable credit, however, belongs to producer and star John Boyega — he of the current "Star Wars" franchise — who brings considerable charm to an exercise that otherwise exhibits a lot more love toward its mechanical elements than its human ones.In a clever callback to the original, Boyega's Jake is the son of the character played by Idris Elba, who sacrificed himself a decade earlier in the battle to defeat the Kaiju, the enormous beasts that entered our world bent on destruction. During the relative peace that has followed, Jake has washed out of the Jaeger program — that is, the giant robots built to defend us — and become a petty criminal and general screw-up, a situation that obviously won't be allowed to last.Faced with incarceration, Jake reluctantly rejoins the Jaeger force, where he's paired with an old antagonist, Nate (Scott Eastwood), as well as a bunch of raw recruits, whose banter and squabbling mixes "Top Gun" with the general level of discourse in a Disney Channel movie. There are also several holdovers from the previous film (not that you'd really remember), including Charlie Day, Burn Gorman and Rinko Kikuchi, amid a distinctly international cast. (That surely isn't an accident, given that the previous movie grossed more than three-quarters of its total haul outside North America.)To its credit, "Pacific Rim Uprising" doesn't suffer from any pretentions about what it is, which proves kind of refreshing. The plot, in fact, basically just bumps along between huge battles that leave skyscrapers scattered as if they were tinker toys. A climactic sequence even takes place in Japan, which consciously evokes the "Godzilla" movies.That said, the paper-thin characters do produce some groan-inducing scenarios, such as Adria Arjona as a Jaeger member who's dating Nate, and is basically on hand just to give Jake and Nate something to argue about — and gin up a bit of comic relief — when they're not moving in unison to operate their mechanical man.Given its generic resemblance to so many other projects, "Pacific Rim" was defined in part by the sheer size of its combatants (take that, Transformers), a dimension that's also conveyed in the visual scope here.Yet while the robots might be bigger than ever, to paraphrase Norma Desmond, this is one of those instances where it's the sequel — even to a pretty forgettable original — that got smaller."Pacific Rim Uprising" premieres March 23 in the U.S. It's rated PG-13.