Every once in a while, Jason Blum’s outfit, which usually produces junky horror movies in an assembly-line fashion, comes up with a surprise winner. The most notable example was “Get Out.” Writer-director Leigh Whannell’s “Upgrade” isn’t on the same level. It certainly lacks originality, being little more than a cinematic stew combining elements of “The Terminator,” “Robocop” and “2001.” But if you’re willing to put your brain on hold for the duration, it’s a pretty enjoyable action lark.

Set in the near future, the plot first introduces the Traces, a married couple who are loving but rather dissimilar. Asha (Melanie Vallejo) works in high tech, while Grey (Logan Marshall-Green) restores classic cars while listening to vinyl LPs. They go out together one night to deliver his latest project to its buyer, he driving the restored beauty and she following in her futuristic, self-driving vehicle. The customer is Eron King (Harrison Gilbertson), an eccentric tech mogul who shows the pair his latest invention called Stem, an experimental computer chip that he describes as a better brain, waiting to be installed in a human body. They are properly impressed but understandably skeptical.

On the drive back home, Asha’s car goes berserk, breaking down in a dangerous part of town, where they’re attacked by a band of thugs, who kill Asha and severely injure Grey. Paralyzed, the despondent man is left with the possibility of being wheelchair-bound for the rest of his life, even as the police investigation headed by Cortez (Betty Gabriel) seems headed nowhere.

Venturing outside his fortress home, Eron appears and makes Grey an offer: he’ll insert Stem into Grey’s spine, and the device will take over his nervous system and make it possible for him to walk again. Grey initially declines but eventually accedes, though he is careful to keep his newfound ability a secret.

That becomes even more of a necessity when he begins to hear Stem talking to him (the smooth, silky HAL-9000 voice is by Simon Maiden), suggesting ways in which it can help him locate the men responsible for Asha’s death so he can take the vengeance he lusts after. When Grey locates the first of them, the confrontation goes poorly until Stem offers to take over his bodily movement. That’s when he becomes a fighting machine that takes care of business decisively, though he’ll continue to feign paralysis to lull his opponents into a false sense of security—as well as keeping the increasingly suspicious Cortez at bay.

As usual, Whannell, who co-wrote the original “Saw” flicks and the “Insidious” pictures, has some tricks up his sleeve, contriving an ingenious set-piece in a seedy bar (where, later, one of the cleverest—and least explicitly brutal–killings in the movie occurs) and a suspenseful sequence in which Stem is being shut off remotely and an increasingly weak Grey must get help from a notorious computer hacker in order to retain his mobility. He also comes up with a twist for the final reel that presents Trace with an opponent named Fisk (Benedict Hardie) who is every bit his equal, if not more, and inches the story into “Matrix”-style territory (though on a budget that would probably not even cover the catering costs on that picture).

In fact, the special effects throughout “Upgrade” are on a pretty modest level. To compensate, it offers good action choreography, both in the hand-to-hand, martial-arts style fight sequences and in a car chase. The acting is pretty rudimentary—Marshall-Green is inexpressive, though he handles the role’s physical requirements well enough, and Gabriel, the spooky housekeeper from “Get Out,” can’t seem to get a handle on the largely ineffectual Cortez. But Gilbertson manages to endow Eron with a genuinely creepy vibe. Though the technical side of things is hardly impressive, Stefan Duscio’s cinematography gives the settings an appropriately seedy ambience and Andy Canny’s editing keeps things moving along briskly.

Whannell has not managed to give Blumhouse another movie anywhere near the quality of Jordan Peele’s, but though “Upgrade” is little more than a mash-up of ideas from lots of earlier movies (many of them better—having the opening credits spoken rather than printed even calls to mind “Citizen Kane”!)—it has enough vigorous action and mordant humor to make for a fairly engaging hour-and-a-half.