The main source of tension in Underwater isn't the claustrophobic fate of a small crew of oil workers trying to fend off bloodthirsty sea monsters after their drilling rig—stationed seven miles beneath the ocean—is destroyed. It's waiting to see when and if this thriller from director William Eubanks and screenwriters Brian Duffield and Adam Cozard will completely fall apart.
From the start, prospects for Underwater don't look good: There's a monotone voice-over from Nora, the haunted and exhausted-looking engineer played by Kristen Stewart, who's attempting to say something profound about… something. And as she's brushing her teeth, she kindly participates in a glaring bit of foreshadowing by rescuing a spider from the kitchen sink.
But as the shit goes down, and Nora and the few survivors—a kindly sea captain (Vincent Cassel), a young couple (Jessica Henwick and John Gallagher Jr.), the comic relief (walking nightmare T.J. Miller), and a token Black character who's promptly killed off in the first 20 minutes (Mamoudou Athie)—slowly make their way toward a possible escape route, Eubanks somehow manages to keep this leaky ship afloat.
The filmmaker leans into the terrifying premise of being stuck under the sea, where there's no natural light and the potential of running into a creepy creature is high. Things get murky when the crew makes a trek across the ocean floor, and it becomes hard to tell which ill-fated character is in which bulky diving suit. Still, the notion of running out of air or succumbing to the ungodly amounts of pressure down there is ever present and entirely unnerving.
What's also present is a nagging awareness of how much better all this could have been. The notion of being stranded far below the surface of the sea is such a good premise that it doesn’t need the addition of water-bound demogorgons, just as it doesn't need any kind of emotional backstory for its characters. Just put 'em in danger and see what happens! Eubanks also crams in a few dull hero shots and a "getting shit done" montage that quickly fizzles out.
Yet none of those issues sink Underwater. It’s continually rescued by the committed work of a cast that (with the exception of Miller) it doesn’t deserve. And its spry pacing and nerve-jangling set pieces offer exactly the kind of dopamine blasts that help gloss over its faults in logic and filmmaking skill.