Despite being met with mixed reviews upon its release in 1979, the massive box office success made it clear that audiences loved Ridley Scott’s Alien. Its first sequel wouldn’t come for another seven years, but the interim was filled with a variety of imitators hoping for a piece of the intergalactic pie.

The Italians were first to strike, rushing the boldly titled Alien 2: On Earth into theaters less than a year after Alien‘s release, and Luigi Cozzi’s Contamination followed shortly after. Not surprisingly, Roger Corman wasn’t far behind. Never one to miss an opportunity to make a quick buck, the trailblazing producer oversaw Galaxy of Terror for release in 1981 and followed it up with yet another Alien knock-off, Forbidden World, in 1982.

Both Corman productions have their charms. Galaxy of Terror is more blatantly derivative of Alien, but its cast features horror icons Robert Englund and Sid Haig and the crew includes a young James Cameron and Bill Paxton. But Forbidden World (also known as Mutant and as Subject 20) — which celebrates its 40th anniversary this week — is the more interesting case study.

In true Corman fashion, he decided on a whim during the production of Galaxy of Terror that he wanted to utilize a space ship interior before the set was taken down. He gave Allan Holzman, who had edited a few pictures for him and wanted to direct, a matter of days to conceive a prologue to be shot on the set that weekend, with the rest to be written and filmed months later.

Holzman’s original concept was “Lawrence of Arabia in space,” but Corman deemed the idea too expensive, so they agreed to do something in the vein of Alien instead. Jim Wynorski (Chopping Mall, Beastmaster 2) and R.J. Robertson (Beastmaster 2) came up with a treatment in part inspired by Corman’s Attack of the Crab Monsters, for which they receive story credit, and then first-timer Tim Curnen was hired to write the screenplay.

Forbidden World opens with a hypnotic, pulsating visual before pulling out from the monitor to reveal a spaceship cockpit piloted by SAM-104, an android that looks like a cross between Star Wars‘ stormtroopers and Battlestar Galactica‘s Cylons. The emergency signal goes off, setting the plot in motion. Taking a lead from 2001: A Space Odyssey, the scene is set to classical music (Beethoven’s “The Piano Concerto No. 1”) as quick flashes of footage from later in the movie provide near-subliminal stimulation.

SAM awakens Mike Colby (Jesse Vint, Silent Running) from his cryogenic slumber, informing the commander that his flight home has been diverted. He’s being rerouted to the remote desert planet of Xarbia to address an accident at a high-security research facility, where they’re experimenting with genetic engineering to create a new food source.

Upon arrival, Colby meets the team: head of research Dr. Gordon Hauser (Linden Chiles), genetic synthesis expert Dr. Barbara Glaser (June Chadwick, V), lab assistant Tracy Baxter (Dawn Dunlap), chief of bacteriology Dr. Cal Timbergen (Fox Harris, Repo Man), lab technician Jimmy Swift (Michael Bowen, Kill Bill), electrician Brian Beale (Ray Oliver, Child’s Play), and head of security Earl Richards (Scott Paulin, Teen Wolf).

One of the facility’s experiments has gone wrong, leaving a genetic mutant known as Subject 20 on the loose in the space station. Colby wants to terminate it and go home (“If it moves and it’s not one of us, shoot it.”), but the crew convinces him to help contain it. No doubt inspired by the Xenomorph’s unique life cycle in Alien, Subject 20 is a metamorph whose genetic structure mutates as it grows, and the creature is largely kept obscured by shadows and fast cuts.

Subject 20’s final form — something like a spider-Xenomorph hybrid made out of paper mache — is less impressive than some of its earlier stages, but the journey is a lot of fun. The film features prosthetics by Steve Neill (The Stuff) and special makeup effects by John Carl Buechler (Friday the 13th Part VII, Halloween 4) with uncredited work by Mark Shostrom (Evil Dead II, A Nightmare on Elm Street 3).

Holzman (who went on to win two Emmy awards for Survivors of the Holocaust, a 1996 TV documentary special he directed and edited for Steven Spielberg) served as his own editor on the picture. He employs some judiciously frenetic cutting that gives the film an artful touch. It also borrows effects footage from Battle Beyond the Stars, another Corman sci-fi production edited by Holzman.

The cast is committed but perhaps none more so than Harris, whose character is introduced to the audience with a choice quote: “Welcome to the Garden of Eden. We play God here. We create life. The only trouble is some of the life we create just won’t behave.” His character is reminiscent of Day of the Dead‘s Dr. Logan, with both mad scientists delivering scenery-chewing performances.

Despite being only his second feature as director of photography, Tim Suhrstedt displays a knack for elegant camerawork and lighting in spite of the low budget. Even the gratuitous nudity and goopy gore, exploitative as it is, plays more tastefully than most of its contemporaries. It comes as no surprise that Suhrstedt went on to shoot the likes of Bill & Ted’s Excellent Adventure, Office Space, and Little Miss Sunshine.

What is surprising, however, is that composer Susan Justin‘s career didn’t take off in a similar fashion. She may have gotten the gig because she was Holzman’s wife at the time, but she bears a dynamic electronic score that fluctuates between spacey synthesizers and new wave territory with prog rock flourishes. It was her first soundtrack, but she only went on to do a handful more (’80s slasher The Final Terror and Holzman’s Grunt! The Wrestling Movie among them).

The enterprising production design by Christopher Horner (brother of Aliens composer James Horner) effectively elevates the film’s production value. Along with the sets recycled from Galaxy of Terror — some designed by Cameron using McDonald’s takeout cartons — the art direction features modular furniture, vaguely futuristic gizmos, and colorful lights.

Forbidden World’s 77-minute theatrical cut is a straight sci-fi horror outing as a result of Corman demanding all humor be removed after audiences laughed at a test screening (during which an angry Corman allegedly struck a cackling viewer). The original director’s cut, under the title Mutant, runs 82 minutes and features levity along with other extended/alternate bits. Both versions have their advantages; the theatrical cut is comparatively dry but better paced.

Corman produced a remake of Forbidden World under the title Dead Space in 1991. Directed by Fred Gallo and written by Catherine Cyran (Slumber Party Massacre III), it stars Marc Singer, Laura Tate, Bryan Cranston, Judith Chapman, Randy Reinholz, and Lori Lively. Although the general plot is the same, the remake most notably gives the mutant an updated look.

Forbidden World is a cheap B-movie, no doubt about it, but for a quick knock-off it offers an unexpectedly unique vision. It may be but a footnote in Corman’s storied career among several hundreds of productions, but Alien fans will find plenty of cosmic, campy fun. It’s available on Blu-ray and DVD from Scream Factory (with both cuts) and is currently streaming on SCREAMBOX, Tubi, Freevee, and Shout Factory TV.