One of the great gifts Ridley Scott’s 1979 horror classic Alien brought to the world was a space monster that felt like it had a little science behind it. It’s standard for the creatures in creature-features to get scarier as the movie goes along, but Alien writers Dan O’Bannon and Ronald Shusett came up with a particularly plausible reason for their xenomorph antagonist to keep evolving into more threatening forms: its species has a life cycle, with stages inspired by insects. The new space-thriller Life borrows a lot of its broad ideas and narrow story beats from Alien, to the point where it feels like a cover version of Scott’s film, and one of the elements it most prominently borrows is the idea of an alien that grows physically larger and more deadly as the action builds. But Life lacks that satisfying next step, where it adds the background that makes the unlikely seem reasonable. Life is a sleek, effective thriller, sometimes scary and often visually impressive. But too often, its reasons for doing absolutely anything amount to “because this is the way Alien did it.” 

The film starts aboard the International Space Station, which is retrieving a lander that scooped up Martian soil samples, then was thrown off its planned trajectory by space debris. Most of the ISS crew are serious people who even make their jokes in hushed near-whispers: Russian mission commander Ekaterina (Olga Dihovichnaya), medical officer David (Jake Gyllenhaal), British xenobiologist Hugh (Ariyon Bakare), Japanese systems engineer Sho (Hiroyuki Sanada), and Miranda (Rebecca Ferguson), from the CDC. Only flight engineer Rory (Ryan Reynolds) talks like he isn’t being polite in a library. He actually talks exactly like Reynolds’ character in Deadpool, though with the obscenity knob turned way down — he’s brash, babbly, and funny, with a smartass energy that’s welcome in such a reserved space. (Screenwriters Rhett Reese and Paul Wernick also wrote Deadpool, but they reserve their humor here for a small window of the film before things get grim.)

Eventually, the Martian soil samples make it onto the station, and Hugh is ecstatic to find they contain perfectly preserved single-celled organisms, which he immediately rushes to reanimate. And events fall out from there, as poorly as in any of the endless horror films where scientists foolishly play God and get dramatically punished — or at least where scientists bypass sensible, rigorous experimental protocols in order to move things along at a cinema-friendly rate. Before long, the crew is at odds with a rapacious alien, incongruously named “Calvin” by an Earthside elementary-school vote. There’s something particularly undignified about getting messily murdered by something named Calvin, but that doesn’t keep the ISS crew from consistently using the name in their hushed, serious voices as the creature picks them off one by one.

For someone who’s never seen Alien — or Alfonso Cuarón’s terrifying 2013 space-survival thriller Gravity, which Life also mimics a fair bit — Life could largely be a dramatic, satisfying experience. Director Daniel Espinosa (Safe House) can’t top Gravity’s terrifying spacewalk scenes, with the sense of Earth looming over astronauts like an immense, inimical shadow. But he does set up plenty of extremely convincing zero-gravity action, with his cast casually buzzing around the ISS like bees in a hive, steering themselves with hand-and-footholds, or working upside-down relative to the audience. That sense of “there’s no up in space” is particularly strong in Life, and with Espinosa’s camera swirling around the cast in long, dizzying takes, the disorientation makes for a solid thrill-ride experience. It also makes things scarier when Calvin starts posing a significant threat. The station is a sterile, claustrophobic place to begin with, and with so little warmth in Espinosa’s chilly visual aesthetic, and no clear up-or-down orientation, the ISS lacks any sense of comfort or familiarity. There’s no sense of a safe haven where the characters can retreat.

The zero-G setting ramps up the stakes in another way: Calvin was designed for zero gravity, and navigates it like a native. Watching it cruise through the ISS at breakneck speeds is like watching the first fast-zombie movie after a lifetime of slow-zombie movies. Calvin’s one advantage over H.R. Giger’s much more id-activating xenomorph design is its speed and grace in a setting humans can only become comfortable with up to a point. The filmmakers draw significantly on terrestrial octopuses for Calvin’s problem-solving abilities and boneless escape routines, but when it starts chasing down crew members, it’s more like a cheetah running down hapless antelopes.

But there’s still a sense of redundancy to nearly everything that happens in Life. Whether the crew is sitting down to a cheerful meal together, fighting over whether to let a compromised crew member out of quarantine in a panic-inducing situation, or figuring out how to deal with an escape pod compromised by an alien, they’re walking through Alien’s plot beat for beat, sometimes nearly scene for scene. They can only come across as worse by comparison. Life spends a little more time establishing its characters’ distinct personalities than Alien, and to the filmmakers’ credit, they find some creative, awful, unexpected new ways to die in space. They also evoke plenty of the inevitability and isolation that ramps up the stakes in any horror movie.

But too much of Life is nakedly cribbed from a better movie, and too much of it is inherently self-important and silly. David’s character is the worst offender, with the most awkward scenes and lines, some of them bordering on bad comedy. When he tells Miranda that as a traumatized military vet, he doesn’t want to go back to Earth because “I like the hum up here, and the air,” he sounds like a dopey space-age Forrest Gump, trying to turn a monotonal, hyper-simplistic statement into a manifesto. When he busts out Goodnight Moon for a dramatic, emotional reading at a critical moment, the entire film threatens to fall down the gravity well of its own idiocy. It’s a moment designed for endless parody; surely Saturday Night Live is already queuing up a guest spot where Gyllenhaal laboriously reads other children’s books in the middle of deadly catastrophes.

And the closer Life gets to the climax, the more balls its story drops. One of the most crucial action scenes is rushed, visually muddled, and hard to follow. The story loses any sense of its characters as individual people, and turns them into generic horror-movie stooges lining up to die. A development allowing them to track Calvin through the ship is abruptly forgotten. And as the novelty of Calvin’s appearance and behavior wears off, it starts to look more and more ridiculous, especially as it stops developing into something increasingly frightening, and just becomes a free-floating CGI effect. Life front-loads its best scenes into the film’s early going, and everything from there is a slow free-fall downward into a fairly silly place. It’s okay to cover the classics; practically every musician wants to play around with their idols’ work. But Life feels like a strictly subtractive cover of Alien that loses too much of what made it memorable, and doesn’t bring enough new to the table.