Between "Metalstorm: The Destruction of Jared-Syn" and "Yor: The Hunter From the Future," it was a pathetic weekend for superheroes and snappy titles.

Unless you relish new contenders for the Worst Movies Ever Made anthologies, neither of these clownishly farfetched and inept adventure spectacles could possibly justify the waste of time or moviegoing allowance.

Now winding down the summer at various area theaters, these low-tech klunkers may be readily identified as poor man's versions of pictures that left plenty to be desired in their own wrongheaded right. "Metalstorm," which follows a space ranger named Jack Dogen into hostile territory in pursuit of a power-hungry renegade bent on fomenting planetary strife, is the poor man's "Spacehunter," right down to an inferior grade of 3-D filming and badlands location shooting.

A certain amount of advertising confuses the pedigree by invoking "The Road Warrior." And the only dynamic performer in "Metalstorm," Mike Preston as the villain whose demise is incorrectly anticipated in that great anticlimactic subtitle (almost as choice as "The Woman They Almost Lynched"), was recruited from the supporting cast of the George Miller classic.

Nevertheless, when this borrowing is taken into account, along with the cribs from "Star Wars" and other obvious sources, "Metalstorm" remains "Spacehunter" at an amateurish level of production.

In fact, amateurish may be putting it kindly. Perhaps a term like neoprimitive is necessary to suggest a quality of illusion that takes you back to the terrain and ambience of science-fiction thrillers that were really strapped for financial and imaginative resources. "Metalstorm" recalls movies such as "Robot Monster." While more elaborate, it also exudes the aroma of something desperately hustled onto celluloid one afternoon on location with limited stock and non-pros in the leads.

"Yor," a name that inspires such delightfully silly, unspeakable lines as the heroine's, "Yor, you're so different from the other men I've seen," is a self-evident spawn of "Conan the Barbarian." Partaking of a deliberate new confusion of motifs also used in "Krull" and the upcoming Lou Ferrigno remake of "Hercules," it scrambles ancient and futuristic illustrative details. A muscle-bound caveman in loincloth, funny shaggy boots and an even funnier shaggy blond mop, Yor is introduced running about the rocks and wielding the wickedest battle-ax of antiquity, a stroke that proves too much for both prehistoric reptilian monsters and rapacious Neanderthals. After rescuing a tribal cutie (Corinne Clery, a far more photogenic adornment in "Moonraker" and "The Story of O") and her grizzled guardian, Yor is maneuvered around a combative circuit that leads to an island outpost of advanced civilization, controlled by Overlord, a villain with delusions of master-race grandeur.

His most amusing delusion is fixing on Yor as the ideal specimen for the masculine component of his new breed. Not that he's daft enough to want any of Yor's mental capacities. It's brainless brawn that he craves, so leading man Reb Brown's Yor is desirable from the neck down; Overlord plans a customized computer renovation for that roomy upper story. Ridiculous as Brown looks loping around the screen in his moronic grin and blond Tarzan disguise, he at least cuts an amiably stoogy figure of heroism.

Jeffrey Byron, the lead in "Metalstorm," seems more rigidly robotic than the mechanical menaces that occasionally threaten him, and when he has to do hard stuff like grit his teeth or pretend to pass out, the results are definitive illustrations of How Not to Act if you want to avoid being giggled at.

In all fairness, Byron seems to be at the mercy of a director, Charles Band, whose sense of things is exceedingly dim. (It runs in the family: his father, Albert, who helped produce "Metalstorm" and may be remembered by readers of Lillian Ross' "Picture" as John Huston's beleaguered assistant on "The Red Badge of Courage," directed some of the most forgettable features of the '60s and '70s.)

For example, the hero faces about three seconds of danger from a blotchy electrified monster that shrivels to nothing when lured into stepping on a wet spot. In another sequence the heroine (Kelly Preston, matching Byron's cigar store Indian, expression for expression) directs a laser blast at a pursuing dune buggy (the vehicle of choice in this science-fiction environment) and somehow hits it through or over or around a sand dune.

Though grievously overmatched, the hero prevails in a hand-to-hand combat with cooking skewers while manacled to a Cyclops. After countless deflating perils and dune buggy chases, the hero eventually loses the villain inside a tackily animated time warp, allowing the filmmakers to insult the audience further with the threat of a sequel.

Really, don't bother. Even gluttons for dumbness may find it easy to refrain from second helpings of "Metalstorm" and "Yor." METALSTORM: THE DESTRUCTION OF JARED-SYN

Directed by Charles Band; screenplay by Alan J. Adler; director of photography, Mac Ahlberg; production coordinator, J. Parker Carr; edited by Brad Arensman; music composed by Richard Band; produced by Charles Band and Alan J. Adler. Presented by Universal Studios. Running time, 84 minutes. Rated PG. THE CAST Dogen . . . Jeffrey Byron Jared-Syn . . . Mike Preston Rhodes . . . Tim Thomerson Dhyana...Kelly Preston Hurok...Richard Moll Baal...R. David Smith YOR, THE HUNTER FROM THE FUTURE

Directed by Anthony M. Dawson; screenplay by Robert Bailey and Anthony M. Dawson; director of photograghy, Marcello Masciocchi; production managers, Michele Germano and Roberto Onorati; edited by Alberto Moriani; produced by Michele Marsala. A Diamant Film production presented by Columbia Pictures. Rated PG. THE CAST Yor . . . Reb Brown Ka-Laa . . . Corinne Clery Overlord . . . John Steiner Ena . . . Carole Andre Pag . . . Alan Collins