David Robert Mitchell had a breakthrough in 2014 with It Follows, a taut shot of lo-fi supernatural horror that owed its sustained creepiness and visceral scares in large part to its skilled use of practical effects. The writer-director veers in the opposite direction with The End of Oak Street, a batty serve of Mesozoic mayhem in a modern suburban cul-de-sac in which actors spend a lot of time — on occasion, convincingly — fleeing something from the digital toolbox to be penciled in later. “I want to remember this insane, stupid moment!” says Anne Hathaway’s character when faced with the startling sight of two dinosaurs madly humping against the side of a house. Oh, hunny.

That kind of cheeky humor is sprinkled throughout, and the audience at a press-and-public preview was certainly laughing up a storm, both in moments where the comedy was intentional and others where…well, who knows? While it’s mindlessly entertaining in a big-dumb-fun kind of way, this is a movie that doesn’t seem to know what it wants to be, beyond a worshipful homage to 1980s Amblin, canonical Spielberg in particular. But lead producer J.J. Abrams already went there with comparable strengths and weaknesses in 2011’s Super 8.

The movie opens on a 1982 summer block party at which frustrated housewife Denise Platt (Hathaway, working below her pay grade) doesn’t hide her irritation with underachieving husband Greg (Ewan McGregor), who has neglected to tell her he was laid off from his job weeks ago. Meanwhile, he’s sneaking slugs of whiskey in the garage and delivering pizzas, like a flaky college kid. 

Their daughter Audrey (Maisy Stella, so delightful in My Old Ass) is a smart, mid-teens science and astronomy geek who defies the stereotype by also being cool, with hints of a burgeoning sexuality that departs from the retro popcorn movie norm. She’s protective of her brother Brian (Christian Convery), in his early teens, and sensitive in her reassurances when he worries that tensions between their parents might lead to divorce. 

A bit of a whiner, Brian carries a bow and arrow everywhere but might be the most inept archer in the history of kids’ adventure movies, hitting a target only once, when it’s too slow and bulky to miss. In a touch that stretches the reference frame from Steven Spielberg to Stephen King, Brian is one of an inseparable quartet of friends whose makeup is right out of the regulation playbook — two white kids, one of them bullied, a Black kid and a chubster. But since the other three are never heard from again after an early scene, this seems as self-conscious a nod as the shots of Brian zooming around the neighborhood on his bike.

The story’s inciting incident follows mysterious flashes of blinding light in the night sky, accompanied by fierce winds and deafening noise. These unexplained phenomena end just as abruptly as they begin but are sufficiently unsettling to put the Platts’ adorably feisty Australian cattle dog Starbuck on high alert. The morning after one of these events, the street is suddenly cut off from the rest of town, surrounded by bodies of water and thick tropical jungle, with unseasonably steamy temperatures.

Out of this Twilight Zone scenario, prehistoric beasts start emerging from the vegetation, the skies and the water, each of them bigger and more vicious than the one before. These time-travel creatures, along with Hathaway, are the movie’s best asset. Watching them rifle through garbage cans, trample fences, toss cars around like toys or slurp up soft serve from an overturned ice cream truck cannot not be fun. Not to mention seeing them rip apart an annoying neighbor and bite the head off another. The Platts warned you to get inside, lady.

The most distinctive of the dino design features is the densely feathered outer covering of some of them, like emus raised too close to a nuclear reactor. My favorite was a chunky mile-long snake — a Titanoboa, though Fat Bastard would be a better name for it — that slithers around like a sloth until it turns aggressive, exposing a mouthful of spiked teeth. The CG creature work is generally slick, aside from a scene in which the camera gets in a little close to huge, armored herbivores with cartoon eyes that look like they belong on plastic Mattel toys.

Naturally, the struggles of the Platt family to stay alive — much like the Delgados in Netflix’s new streaming original, The Last House — depend on them having each other’s backs, in this case rediscovering a closeness that seemed to be fragmenting early on, before the marauding interlopers crashed their world. 

If you’re hoping for a thorough explanation of how two hundred million years or so of distance got smushed together, a few rushed words from Audrey about tremors and time portals is as close as you’ll get. As for the exit strategy — involving large spheres of light, like Glinda’s means of travel in The Wizard of Oz — best not to give it too much thought.

There are wild inconsistencies in the way the kids are drawn, notably Audrey, who one minute is witnessing carnage and spouting scientific theories and the next minute is out in the car, parked in the driveway, weeping while singing along to Steve Winwood on the radio. Are you trying to draw attention, girl? Brian’s heedlessness makes a little more sense when he dashes out to chase his beloved Starbuck. 

McGregor, to put it bluntly, is terrible, and not just because his American accent keeps slipping. Admittedly, he’s stuck playing a drip, but even when he’s out on the streets wielding a sledgehammer, there seldom seems to be much at stake in his shambolic performance.

Hathaway, on the other hand, is the essential glue holding the film together. Denise — a name that kept making me wish this were an all-out schlocky B-movie with Denise Richards — is basically an Anne Tyler character in a Michael Crichton novel. She’s a woman looking around now that her kids are growing up and acknowledging her lack of fulfillment, feelings expressed in a novel she’s secretly been writing, in which the protagonist keeps a suitcase packed in the hope she might one day run away from her suffocating life as a wife and mother.

When the situation gets hairier, Denise is the fearless one unloading shotgun bullets into leathery great reptiles, and there’s real enjoyment in watching Hathaway run screaming from a hangry beast in close pursuit. Though how the Platts can be chattering away in someone’s front yard without noticing there’s a monster the size of a house creeping up on them is just one of many risible moments in Mitchell’s script.

That said, there’s no shortage of decent scares, all amped up by Michael Giacchino’s frantic score and sound design that rips through you like a surprise bowel movement. Denise’s arc of coming around to a new appreciation for Greg after almost losing him is strictly by-the-numbers, and the escape from their life-threatening predicament is too laughably easy to be anything but anticlimactic. But the movie has its giddy charms, Fat Bastard the nasty snake chief among them.

Working with his regular cinematographer Michael Gioulakis, Mitchell gives the movie a dynamic visual kick, with lots of vigorous tracking shots, rapid zooms and split diopters. And production designer Maya Shimoguchi has provided him with a playground full of character and period detail in the Platts’ house.

After the early promise of his captivating debut feature The Myth of the American Sleepover and his confident leap into horror with It Follows, the director appears to be slumming it here, dipping his toes into blockbuster waters that inevitably evoke Jurassic Park and all its children, in a half-jokey tone that tends to undermine the terror. It’s been eight years since Mitchell took a critical and commercial bashing with his self-indulgently Lynchian L.A. noir Under the Silver Lake — a movie with plenty of staunch defenders — making this sweetly silly nostalgia exercise seem an underwhelming return. But hey, at least he appears to be having a good time.