Recent accidents involving amusement park attractions might make you feel a bit queasy about the plot of “The Nut Job 2: Nutty by Nature,” the sequel to the surprise 2014 animated hit about ne’er-do-well Surly the Squirrel and his bands of friends inhabiting Liberty Park in a town called Oakton. The scenario pits the critters against an evil, greedy mayor who orders their home to be bulldozed to make way for a profit-generating amusement venue that he fills with old, condemned rides. (Happily we’re never shown people getting onto them.) The movie also includes an opening bacchanalia depicting Surly and his fellow park-dwellers gorging themselves on the nuts that fill the basement of an abandoned store and a scene, about halfway through, in which a dog regurgitates his food and then promptly bolts it down again. Yuck!

Otherwise the movie is superior to its predecessor, though still mediocre by the standards of the best family-friendly fare, boasting lots of mindless hubbub but a distinct lack of wit or memorable lines. Of course, in the end it offers morals designed to instruct kids about values. After that store is destroyed by a boiler explosion caused by the squirrels’ carelessness, for example, Surly (voiced again by Will Arnett) and his buddies, who have been accustomed to enjoying the free ride it afforded, must accept the wisdom in the injunction of his girlfriend Andie (Katherine Heigl) that they should go back to getting their food the honest, old-fashioned way—through the hard but fulfilling work of collecting acorns from trees. Don’t take shortcuts!

And when nasty Mayor Muldoon (Bobby Moynihan, a caricature of the corrupt Southern pol) begins destroying the town’s last park (the other he’s already turned into a golf course, like some other politicians you might know), the critters not only band together to stop him, but enlist help from an unlikely ally—a bunch of white mice trained in martial arts by their leader Mr. Feng (Jackie Chan), who, in a running joke, takes umbrage at being called cute, though he undoubtedly is. (The mice, you see, were earlier ejected from their home, the new gold course, and so are willing to assist another rodent species.) All should join together to resist the despoliation of the environment!

There’s also an extended sequence in which the movie slips into sheer sentimentality, when Surly grieves over his injured pal, the nearly mute Buddy (Tom Kennedy), remembering how the scrawny fellow had once saved his life and has been his loyal companion ever since. Seeing Surly blubber is one step in his transformation from rascal to hero, of course, but the moment seems to go on forever. (At least the makers don’t have that old song, “My Buddy,” playing in the background—for which one can be truly grateful.) Friendship is important!

The movie does have one thread that provides some genuine amusement—an incipient romance between Precious (Maya Rudolph), the pug from the first picture, and Frankie (Bobby Cannavale), the pampered pet of the mayor’s daughter Heather (Isabela Moner). Frankie may be the dog involved in that gross regurgitation scene, but the relationship between him and Precious is one of the few really bright things in the movie—certainly more so than that between Surly and Andie.

Unfortunately, it also involves a large role for Moner’s Heather, a squealing spoiled brat who’s easily the most irritating figure on tap. The only excuse for a character like this in a family movie is to provide her with a satisfying comeuppance, and the one provided by the writers—like that of her father—is inadequate to the task.

“Nutty by Nature” is loaded with action, and the animators, with a bigger budget than the first film had, do a reasonably good job with it, as unnerving as it might be to watch a burning Ferris wheel rolling around a crowded field with people scrambling out of the way. The character animation, though, is mostly bland, as is the voice work: Arnett, for instance, tries very hard, but is stubbornly incapable of making Surly likable—a real detriment when he’s the central figure in the raucous hubbub and you’re meant to be rooting for him in the final confrontation. Chan’s distinctive tones add some tang to Feng’s contributions, but his “Don’t call me cute!” routine is repeated too much, and his crew of followers, presumably intended as the picture’s answer to the Minions, never develop any personality of their own.

“The Nut Job 2,” like its predecessor, will probably enjoy quick but short-lived success in theatres, followed by a substantial haul in ancillary media—which will probably be enough to justify yet another installment in the series. A little inspiration would be a welcome ingredient next time around.