Little ones are “tougher than we think,” a penguin remarks in Happy Feet Two, and you can tell director George Miller believes it. The animated sequel pulls few punches: It’s overshadowed by more darkness, menace, heartache and anxiety than any talking-animal picture I can think of since, well, Miller’s last family-film sequel, the execrable Babe: Pig in the City. Neither the classic Babe nor the original Happy Feet contained any hint of the darkness of the sequels. Apparently Miller’s strategy is to soften kids up first, then drop the bomb.

Not that Happy Feet Two is a horror show equivalent to the movie I like to call Babe: With a Vengeance, where the heartache was almost uninterrupted from beginning to end. Happy Feet Two does offer moments of comfort, humor and redemption. In its penguin protagonist, now a father with a chick of his own, the sequel has one of the most positive animated father figures in recent memory, along with Pixar’s Marlin from Finding Nemo and Bob Parr from The Incredibles. It’s also worth noting that the animation is far more spectacular this time around. Still, the dominant mood is too grim. It’s nothing I would consider for my own children.

The Oscar-winning original Happy Feet, about an Emperor penguin named Mumble (voiced by Elijah Wood) whose tuneful colony was slow to accept his tap-dancing ways, is fondly remembered by many for its singing and dancing penguins. I think it highly overrated, a lumpy coming-of-age tale soured by inappropriately racy lyrics, explicitly anti-religious/authority/tradition themes, and a coy homosexual subtext. (No, I’m not kidding.)

For what it’s worth, none of these caveats is quite as much of an issue in the sequel. The soundtrack is, if anything, more obnoxious this time around (instead of Prince, Boyz II Men and Elvis, we get Justin Timberlake, Pink and Wham), but at least the filmmakers have the minimal sense to sanitize the lyrics — for instance: “Get your fluffy on” instead of “Get your sexy on.” (Compare that to lines like “I just need your body, baby, from dusk till dawn” in the original.)

Penguin religion is less prominent, although there’s a new false prophet named Sven (Hank Azaria) who is celebrated by the phony guru Lovelace (Robin Williams) from the original. And while there’s some gay-themed humor in a subplot involving a pair of krill, it’s not a key subtext this time.

What Happy Feet Two ramps up is the ecological theme. In the original, human overfishing of Antarctic waters was starving the penguins. Here, it’s global-warming apocalyticism. Ominously crumbling, shifting, melting ice and snow is an ever-present danger; shoots of green crop up in new locales; water pools on the ice, and tsunami-like waves buffet the frozen coast; helpless animals are stranded on shrinking icebergs, etc.

The main plot centers on shifting ice trapping the Emperor colony in a sort of ice valley where, cut off from the sea, they are in danger of starving. As a central conflict, this predictably restricts the dramatic possibilities as much as it does the penguins’ movements. There will be escape attempts and rescue attempts that fail, and then, finally, in the end, one will succeed. In the meantime, there’s a lot of penguins standing around while the plot spins its wheels in the snow.

Mumble’s mate Gloria (recast as Pink after the original actress, Brittany Murphy, died last year) is trapped with the colony, while Mumble and their young chick, Erik (Ava Acres), are on the outside looking in. Parent-child separation trauma is a major theme, starting with an aggressive elephant seal (Richard Carter) who takes a nasty fall into a seemingly bottomless crevasse while his adorable round-eyed pups look on in horror. Mumble sets that problem straight, but it takes the whole movie to rescue the stranded penguins.

Breaking up the monotony of the main plot, the film intermittently cuts to the largely unrelated comic adventures of Will the Krill and his sidekick, Bill (Brad Pitt and Matt Damon). Will and Bill’s dialogue is strikingly rife with philosophical allusiveness, starting with Will’s initial musings about what lies beyond the world they know, the swarm. “More swarm?” Bill suggests. But Will is convinced that everything has an end (“Look at my tail — that’s where I end”) and is determined to pursue the possibility of freedom. “There is no ‘free,’ Will!” Bill shouts. (Read it again if you missed it.)

By the end, Bill is speculating that perhaps dancing serves “as a temporary release from the existential terrors of existence.” (Another character, in what is admittedly a pretty great moment, sings, “Nothing makes sense in this world! It’s all just a big pile of crazy! And the kings are all fools!” I’m seldom one to fault a family film for presenting challenging ideas, but this is the kind of thing you want context on — context the film doesn’t provide.)

Horrified to find that his world is lunch for large predators, Will strikes out on his own, determined to “move up the food chain.” Repeatedly attempting to dissuade Will from his quixotic quest, Bill suggests, “We can start our own little swarm!” When Will objects that they’re both male, Bill responds, “We’ll adopt! Plenty of krill would count themselves lucky to have me as a partner! I’m a heck of a wingman!”

Before long, Bill’s serenading Will (“Wake Me Up Before You Go-Go” and “Never Gonna Give You Up”), and Will finally gives in, warning, “But no hanky-panky!” This is pretty overt, though it’s basically limited to a few lines between supporting characters, where the first film centered on the conflict between an intolerant society and the “different” protagonist with his nonconformist impulses.

Echoing the absurdity of Will’s quest to become a predator, Sven, billed as a flying penguin, proclaims a gospel akin to The Secret: “If you want it, you must will it; if you will it, it will be yours!” Many penguins, including Mumble’s chick Erik, are swayed by “SvenThink”; Erik even believes that he may actually be able to fly, though his aspirations are destined to come crashing to earth. (Many viewers will immediately recognize Sven as a puffin poser. Here’s a theme parents who wind up watching Happy Feet Two with their kids might highlight: Creatures can’t be something contrary to their nature; God didn’t make krill to be predators, or penguins to fly.)

Erik, like his father before him, struggles to find his place in the world, and Mumble struggles to be a more supportive father than his own papa, Memphis, was. Despite some initial awkwardness, Erik ultimately declares Mumble his hero, and his striking tribute to his dad is one of the film’s most vivid grace notes as well as its best musical moment. On the other hand, Happy Feet Two also subjects us to the depressing spectacle of penguin chicks rapping and striking hip-hop poses. This is the scourge of modern animated family fare, from The Smurfs to Alvin & the Chipmunks. Please make it stop.

What is up with the gratuitously icky moment in which Sven puts some moves on Mumble’s mate Gloria? Apparently he singles her out just to lord it over Mumble, though this is his only moment of such malice. (Sven mostly comes off as pathetically needy and unscrupulous in pursuing celebrity, but still kindly and even heroically helpful to the Emperors in their hour of need.) As part of a group effort to bring food to the trapped penguins, Sven personally brings a fish to Gloria and slyly passes it to her beak to beak; there’s even some tongue contact. This bizarre moment connects to nothing else in the film.

For some reason, even though he’s now a father, Mumble still looks like an overgrown adolescent chick, with downy gray feathers, while all the other adults, including Gloria, have sleek black-and-white feathers. Is this a side effect of being dropped on the ice as an egg by his father in the beginning of the first film? Is Mumble really the way he is because his father dropped the ball? There’s a politically incorrect angle on Happy Feet‘s parable of difference.

Register film critic Steven D. Greydanus blogs at NCRegister.com.

Content Advisory: Some intense menace and action; mildly suggestive content and innuendo, including brief homosexual-themed humor; stressful family situations. Not for younger kids.