Nowadays it seems obligatory to make sequels of even the most mediocre children’s animated movies. “Cloudy With a Chance of Meatballs” was okay—a visually splashy but pretty silly flick with a few amusing characters and some clever riffs on end-of-the-world action movies. But it went downhill toward the close and wound up like a deflated balloon. The follow-up contains some genuinely gonzo eye-candy, but the weirdly imaginative images are wedded to a tired script. Though even more colorful than its predecessor, it manages to take off, but not to stay aloft for ninety minutes.

“Cloudy 2”—which, it should be noted, isn’t an adaptation of the sequel by Judi and Ron Barrett that appeared in print—takes up immediately following the end of the first movie. Goofy inventor Flint Lockwood (Bill Hader) and his pals have succeeded in knocking out his FLDSMDFR, the machine that turned water into food but went berserk, threatening to engulf all of his island home, Chewandswallow, in oversized edibles. The government orders an evacuation of the place and tasks Flint’s boyhood idol, genius inventor Chester V (Will Forte), to handle the cleanup. The wacky, multi-hologram Chester enlists Flint to join him in the task by tracking down the FLDSMDFR and inserting a computer drive into it that will shut it down and prevent future misconduct on its part.

So it’s back to Chewandswallow for Flint and his band—spunky Sam Sparks (Anna Faris), infantile Brent (Andy Samberg), solemn cameraman Manny (Benjamin Bratt), ebullient policeman Earl (Terry Crews, replacing Mr. T), and dour Lockwood pere Tim (James Caan), as well as chattering Steve the Monkey (Neil Patrick Harris)—who are accompanied by Chester’s amanuensis, Barb, a buxom talking ape (Kristen Schaal). It turns out, unsurprisingly, that Chester V is not the selfless scientist Flint had always assumed, but a fellow with his own plans, all designed to profit his so-called Life Corporation.

Those plans involve what the FLDSMDFR is now producing on the island—genetic mixtures of plants and animals, or “foodimals,” that Chester describes as dangerous. Certainly the “cheespider,” a mega-burger that runs about on French fry legs and threatens to gobble up its prey, looks menacing. But others, like an ultra-cute strawberry baby with big eyes and a mournful cry, are sweet, and most of the remaining fruit-and vegetable offspring appear harmless, too. The question that Sam poses to Flint is whether it’s right to shut down the system that gave birth to these creatures and sustains them, and he’s torn between heeding her and going along with his revered master-inventor.

It’s in the portrayal of the mutant menagerie that “Cloudy 2” shows witty artistry. There’s a touch of the daffiness one finds in “Fantasia” and Lewis Carroll to the various hybrids concocted by the scripters, and the Sony animation crew brings entities like huge, ravenous pickles and a taco-crocodile combination to life, setting them against a lush, vivid wilderness background. True, much of the running-time is merely a rather tedious trek through a place inhabited by strange thingies that jump out of the foliage and chase our heroes around, but at least the thingies are amusing cartoon constructs. Unfortunately, the journey does run on, and in the last reel morphs into a typical action-packed confrontation in which the fate of the world is at stake—except in this case it’s the new world fashioned by Lockwood’s invention, which has evolved beyond anything he’d intended. In fact, the whole of the movie could be interpreted as a sort of wacky parable of evolution, but the message it’s trying to impart is garbled. On the one hand it’s clearly a warning about the destructive potential of capitalist greed on nature (no surprise there). But are kids also supposed to draw the disturbing conclusion that fruits and vegetables aren’t far from being cuddly critters too, and that consuming them is somehow wrong? If so, good luck to parents demanding that they eat those string beans or go to bed without desert.

But though “Cloudy With a Chance of Meatballs 2” is kind of bonkers thematically, it does show imagination in the depiction of the wild mutant creatures, and while the humans are bland by comparison, the voice talent does what it can with them (Caan stands out with his gravelly delivery and mournful air, and Bratt’s deadpan delivery is fun). They’re hobbled, however, by the fact that the dialogue is generally uninspired and there’s too much throwaway potty humor.

So the verdict is a mixed one. The movie offers some fantastical visuals, but to enjoy them you have swallow a pedestrian script and a muddled message. It’s trippy in one sense but trite in another, and you have to be picky about savoring the good stuff while pushing the rest to the side of the plate.