“Loki” isn’t the only time-twister onTV this week.

Amazon Prime Video’s “Totally Killer” is basically “Back to the Future” if that ’80s flick was a slasher. That’s all to say that this Jason Blum-produced movie adds bloody suspense to sci-fi comedy, minus a big budget but with enough filmmaking flair to be worth a viewer’s time.

The film’s a great showcase for Kiernan Shipka (“Mad Men,” “Chilling Adventures of Sabrina”),无缝编织漫画线交付to a multilayered, life-and-death dramatic performance. Her Jamie Hughes is a 2023 teenager who doesn’t have a minute for her overprotective mom Pam. But Pam (Julie Bowen of “Modern Family,” who’s a surprisingly deft stunt fighter) has reason for being so cautious — her three best friends were each stabbed 16 times in October 1987 by the never-caught Sweet Sixteen Killer, and Halloween puts her on edge.

So, of course, on this Halloween there’s a terrible tragedy, and soon Jamie is running for her life from the reappeared maniac — dressed all in black with a full head mask that resembles Biff, the bully from “Back to the Future” — and straight into a time machine built by her best friend Amelia (Kelcey Mawema from the “To All the Boys” movies) as a science project.

Suddenly in 1987, Jamie discovers teenage Pam (Olivia Holt, “Cruel Summer”) leads the high school mean girl clique known as the Mollys, who all dress like Molly Ringwald movie characters — and are destined to become the Sweet Sixteen Killer’s victims, unless Jamie can prevent it.

Directed byNahnatchka Khan(“Fresh Off the Boat,” “Young Rock,” “Always Be My Maybe”), “Totally Killer” puts Jamie through the expected time-travel complications: She has to warn people while not sounding like a nut. Nobody believes the truth except Amelia’s equally science-nerdy future mom, Lauren (a wry Troy Leigh-Anne Johnson).

But no matter how hard she tries, Jamie’s very presence starts altering history in frustrating, homicidal ways. Her dad Blake (Charlie Gillespie as his surprising — to Jamie — ripped younger version) and Pam get the hots for each other way too early for their daughter to be conceived, as she was/will be, when they come home from college.

Some of the film’s anachronistic gags inevitably fall flat, but a high percentage of them are well-thought-out. For instance, imagine being the only kid at a pot brownie party who doesn’t get high because she’s accustomed to much more potent 21st century THC gummies.

Naturally woke, Gen Z Jamie disapproves of the chauvinism, casual racism and cigarette smoking that’s everywhere in ’87. There’s also too much talk about fellatio but none performed (period accurate?). But Shipka plays the character resilient and focused; snarky comment made, she’ll shake off whatever offends her and get back to the urgent mission.

Er, make that two missions: Besides saving her mom’s friends, Jamie needs Lauren to get the time machine, built to run on Wi-Fi that has not yet been invented, operational enough to send the future girl home.

When an ’80s fan of “Terminator” and “RoboCop” movies asks Jamie if machines end up killing humanity, she answers, “No. They more just rip apart society via dance videos on TikTok.”

“他们用舞蹈反对我们吗?“20世纪kid asks in horror.

The film’s actual horrific scenes are as clever as its dialogue and serviceably frightening. (Think it’s easy to properly stab someone on a waterbed? You’ll find out.) Despite some gruesome brutality, “Totally Killer” has a very light-on-its-feet quality. But as artificial entertainment goes, this one’s put together with ruthless care.

Khan stalwartRandall Park, who plays the town’s clueless ’80s sheriff, sums up the viewpoint of people who hadn’t seen “Back to the Future” yet: “I hate time-travel movies. They never make any sense.”

If that character survives into 2023, this slinky, satisfying “Totally Killer” will completely change his mind.

Bob Strauss is a freelance writer.