Grade: C

When the first “Guardians of the Galaxy” movie came out three years ago, even those of us who weren’t enthralled by it had to admit that it differed from previous blockbusters of the so-called Marvel Universe, making a smash hit out of what was really a second-(or maybe third-) tier title in the company’s slate of comics, and giving it a much goofier spin than the norm. The result wasn’t much more than a self-consciously hipster version of “Star Wars,” bringing a crew of unlikely comrades together on a mission to save the universe, but it obviously appealed to a huge number of people. You can’t argue with success. (Well, you can, and sometimes should, but it’s hard when box office receipts are concerned.)

The question about the newly-arrived “Vol. 2,” which comes from the same director, James Gunn (who also takes solo writing credit this time around), is whether it can catch lightning in the bottle a second time. Financially, the answer is certainly yes. The movie will make a mint, probably more than its predecessor. But from the entertainment perspective, one has to harbor doubts. To take the “Star Wars” analogy a step further, it’s as though “Guardians” skipped “The Empire Strikes Back” and went directly to “The Return of the Jedi”—omitting the best and winding up at the worst. It will still please the rabid fans, but others may find the drop-off rather precipitous.

The “Star Wars” comparison works in other ways. For one thing, “Vol. 2” is more a kiddie flick than the first picture. It features more naughty potty humor, the sort that seems obligatory in so-called “family” movies nowadays. One of the biggest jokes upfront involves the use of the word “turd,” and there’s actually a throwing-up scene later on. How charming.

The character who does the vomiting, moreover, is Groot, the huge tree of the previous picture (voiced by Vin Diesel), but now turned into a cute little thing (still voiced by Diesel, though there’s not much dialogue involved). He’s used throughout as the figure the camera will turn to for an automatic “Aw!” reaction from the audience. (The entire credits sequence, mimicking that of the first movie, follows him dancing while a huge battler takes place in the background.) It’s basically the same function the Ewoks served in “Jedi,” and we know how well that turned out. No wonder there’s already a slew of Groot toys being hawked—“Dancing Groot,” anyone?

Even more telling, though, is the fact that “Vol. 2” turns out to be about—you guessed it, family (certainly the most ubiquitous crutch of a theme in Hollywood today). Everything is about finding your family (or a family, since it’s always an issue whether biological connection is all-important, or whether one becomes part of a “new” but even more real family). So Gamora (Zoe Saldana) finds her sister Nebula (Karen Gillian), but they’re hostile, indeed murderous toward one another (it’s basically a “daddy always loved you best” business) until at the end, of course, when they’re not. And Rocket, the snide, trash-talking raccoon voiced by Bradley Cooper, learns how to be upfront about his attitude toward his fellow guardians: he’s even the focus of one of the last shots, one that’s as sappy as you could possibility imagine.

The major thrust of the script, however, is Peter Quill, aka Star-Lord, finding his true father: Ego, a celestial, or demi-god, played by Kurt Russell. It seems that Yondu (Michael Rooker), the blue-skinned Ravager, had been meant to deliver young Peter to Ego after his earth mother’s death, but had kept the boy for himself instead. Ego has been searching for his progeny since then, and rejoices at finally making contact by rescuing him and his comrades from assault by the forces of Ayesha (Elizabeth Debicki), the leader of the Sovereign, an alien race from which Rocket had stolen some precious batteries, and Yondu’s Ravagers, whom Ayesha hires to retrieve them and take retribution. But whether Ego’s intentions are good, or Yondu was more of a father to him than Ego was, becomes the crux of the narrative.

There’s another major character in the crew—beefy, heavily-tattooed Drax, played once again by WWE wrestler Dave Bautista. He doesn’t locate a lost family member, but he does get to deliver a monologue about his late wife, and develops—at least insofar as his habit of saying what he thinks, whatever the effect on the hearer, allows—a relationship with Ego’s companion, a sweet-natured, antenna-bearing young lady (Pom Klementieff) with empathetic powers called Mantis.

Of course, all the interpersonal stuff is wrapped up in an orgy of special-effects-laden action set pieces, ranging from that battle against giant lizard that plays out against the opening credits to a typically splashy, earth-shaking concluding confrontation in which each character has his or her own mission of heroism to complete if the galaxy is not only to be guarded, but saved. It also requires a demonstration of self-sacrifice that allows for a teary finale, with what is apparently meant as an outer-space version of a Viking funeral. The visual pizzazz is of the highest quality, of course, but it’s so pervasive that the movie can barely be called a live-action one at all; it’s essentially an animated picture with occasional real actors capering around amid the drawings. Some of the live people, to be honest, are stiffer than the computer-generated figures: Sylvester Stallone appears, for instance, as the head Ravager, and he’s so rocky-like he might as well actually be made of stone.

The others go through their paces with practiced efficiency. Pratt is an agreeable light comedian who makes Peter likable, and can convincingly handle the derring-do; it’s a pity he gets shunted to the side in much of the movie’s second half to provide room for the plot threads involving other characters. Saldana does her stern shtick well enough, and Klementieff is pleasantly off-kilter, but Gillan is rather one note; so is Bautista, but he’s not really an actor at all, and his muscles fill the bill adequately. It’s a pleasure to see Russell strutting around again, doing the sort of thing he perfected in his younger days as an action hero. But even his spry delivery can’t do much with the endless streams of exposition that Ego has to mouth. More successful is Rooker, who brings a sense of fun as well as gravity to Yondu. It helps that with the Ravager’s magic stick he’s at the center of some of the movie’s most engaging, cleverly choreographed action sequences.

Unhappily “Vol. 2” comes up short as an elephantine sequel to a movie that was lighter on its feet and became an unexpected smash; it tries so hard that the strain shows all too clearly. It does a have a few cheerily nutty moments (like one in which Ayesha comes to confer with Yondu on a carpet that her aides must roll out in front of her, step by step). And it will attract a huge audience out of sheer habit, with a third installment in the series inevitable—the half-dozen teasers that are dropped into the closing credits make that clear. But the fact that there are so many of those little bits merely shows how overstuffed it is.