I think its fair to say i was blown away by this. A genuine surprise, even if i did approach it with fairly low expectations. Its exactly what you think it might be, but normally isn’t, in this sort of environment. I’ll try and explain that paradox, but first i should say this review contains spoilers.
1: NO SPOILERS SUMMARY AND CONCLUSION
The film opens very quickly into the disaster with an ‘earthquake’ suddenly threatening the already strenuous life down at the bottom of the mariana trench, where a small team of ‘ologists are trying to dig towards the core for fuel purposes or something. Two or our protagonists are quickly forced to kill a few others to save the integrity of the base, thus leading to guilt and regret, and then the whole films ramps into claustrophobic nightmare after nightmare as the crew struggle to escaped terror at x-hundred fathoms.
Taught, scary as fuck and well worth turning all the lights off for.
Kristen Stewart is a revelation, and i take back anything ill i’ve ever said of her. Technically i was a fan pre-Twilight, when she played Jodie’s daughter in Panic Room, and i openly took the piss for the following several years. But her appearance, and her performance in this, has completely turned me around. She is a role model for the new generation, the Ripley of our age – not just an independent, strong woman but a flawed, human one. Terrified by the declining situation yet headstrong enough to embrace it. And, crucially, this is a film after all, able to toe the line into escapist, bombastic heroism.
2: SPOILERS.

If you start watching any kind of film of this ilk you have three potential expectations. Either that the antagonist is just the plot itself; the whole base is collapsing due to earthquakes and its a bombastic, claustrophobia fight for survival. See also space survival films like Gravity, or Ad Astra, Solaris, etc. Or, the villain is psychopathy itself; prime example in this field is Sunshine, when one of the crew has gone bonkers and is killing people.
Then, you get this. And it can split audiences in two. I’m one of those people that hates films that skew away from the nonsensical and instead delivers frightening jump scares and a showboaty shouty villain man/woman to slaughter the crew before being beaten by our hero in the final moments. But give me a film that hints of monsters and / or aliens and i’m sitting up in my seat. And this film takes its fair time making suggestions, but is unafraid when it plucks up its Alien-inspiration and gives us an octopus facehugger.
Then takes it up a notch to squidmen body shredders.
THEN knocks it out of the park when Kroll answers the call of Cthulu and we are given a massive, titanic behold human comprehension beast from below, which has a mouth so big you could feed it New South Wales without touching the sides. This behemoth Doctor Who monster provides us with devastatingly terrifying underwater gigantism, warmed by thermal vents and prodded into action by our own drills.
So there is a moral to the story. Much as with the words of Saruman of the dwarves; they mined too deep. There are far worse things than orcs in the deepest places of the world.
What new devilry was this? It was a damn good monster movie with a kickass heroine, thats what it was.