YMMV / Underwater

• Alternate Character Interpretation:
  • A slightly more morbid interpretation of Norah's Heroic Sacrifice at the end - maybe she saw letting Emily and Smith survive while she stays behind as a way to be Together in Death with her fiance, while also conveniently blowing up Cthulhu.
  • Are Tian Industries just your stereotypical callous corporation ala Weyland-Yutani who keep messing with things they should leave alone for the sake of profit, or are they actually ran by Cthulhu cultists who intentionally caused the whole accident to sacrifice people to the Great Old One and will continue to go deeper and cause more for the sake of getting closer to their deity? Or, conversely, might their announcement that they would "keep drilling" be a cover story for a joint military/Tian mission to wipe out the Deep Ones without the public finding out such horrors exist?
  • How much did Lucien know about Tian Industry's drilling operations? His locker in the abandoned Shepard station contains a map of the proposed drilling site, along with drawings of pentacles and a drawing of Cthulhu (itself a Shout-Out, being based on a drawing done by H. P. Lovecraft himself). Or could it have been him who tricked his superiors into drilling at that spot with falsified research data, because he was a lone cultist setting up the company to rouse Cthulhu?
• Catharsis Factor: After a whole film of feeling helpless against the horrors of the Deep Sea, Norah gets two people to safety and ensures it by blowing up the entire station - which wipes out all the fish people and the creature itself. With Word of God confirming it's Cthulhu himself, it's very satisfying. And while there's nothing that says he couldn't respawn, clearly Norah hurt him enough that he hasn't retaliated eight months later. Although given that Tian announced it would continue drilling and the reveal that Lucien had some inkling of what was actually down there... perhaps it was all just part of the plan.
• Critical Backlash: Critics were not kind to the film, only giving it a 48% rating on Rotten Tomatoes. Horror fans largely checked it out to see if it was as bad as they said - and many expressed surprise, or were downright shocked and indignant, at the low rating.
• Epileptic Trees: Despite the different production companies rendering such a feat legally impossible, this film was briefly speculated to connect to the Cloverfield multiverse. This was Jossed as soon as the film came out, but this didn't stop some members of the Cloverfield community from finding similarities between the two properties like how one of the actors in this film, John Gallagher Jr., is also in 10 Cloverfield Lane. Funny how it instead takes place in the same universe/mythos of The Call of Cthulhu.
• Genius Bonus: As Youtuber Deusdaecon points out, the name on Norah's shirt in the opening - Pontus Endeavors - is Latin for "Sea", but also a pre-Olympian God of the sea, who was allied with the Titans, hinting at some deliberate decisions In-Universe.
• Older Than They Think: A movie with a female protagonist with short blond hair, still troubled by losing a significant other and even named Nora(h), who must escape from an underwater drilling station owned by a evil MegaCorp that has (unknowingly?) awakened a new species of tentacled monsters, and with climactic scenes of said protagonist confronting the beasts in a pressure suit on the sea floor? It seems the producers narrowly avoided paying royalties to Luis Miguel Ariza for his 2005 novel Kraken. Even some particular scenes, like Norah finding suspicious material in the abandoned station's locker and later punching Emily to force her into a pod, have their equivalent in the novel.
• Platonic Writing, Romantic Reading: Smith and Emily are the only romantic couple in the film, but Emily actually shares many more tender moments with Norah; they hug closely when Emily is introduced, the two of them bond a lot in the third act and Emily tries to prevent Norah from staying behind.
  • Emily's love confession to Smith is even shown via Norah listening to it, as if Emily is talking to her.
• She Really Can Act:
  • Jessica Henwick is of course best known for playing one of the universally loathed Sand Snakes in Game of Thrones and, while she did redeem herself somewhat with Iron Fist (2017), that series was similarly divisive. Here, she helps transform a character who could easily be The Load into a genuine woobie.
  • Similarly, the much-maligned Kristen Stewart defied the hell out of her passive performance as Bella Swan, as Norah is an engineering badass with a cynical edge, who rises to the occasion and even manages to take out Cthulhu in a Heroic Sacrifice.
• Spoiled by the Format: The film's own opening credits spoil the fact that the crew will find unknown and likely hostile creatures. Then again, it doesn't spoil that those creatures happen to be Lovecraftian.
• They Wasted a Perfectly Good Character: Rodrigo gets some good scenes at the very beginning, surviving the initial phase of the disaster along with Norah and being her initial companion as they work their way to the control center, but not only does he die first when he could have averted the Black Dude Dies First stereotype, but he dies from a faulty helmet completely unrelated to the attacking monsters, and with no bearing on the plot.