Should have gotten to its premise 30 minutes quicker (spoilers inside)
Especially considering that the movie spends its first half without developing any characters or building any tension. At one point, the characters come upon 3 dead bodies but carry on like nothing happened. My partner at 1 point asked me if she had fallen asleep and dreamt that entire scene.
It started to get interesting when the inter-personal tensions in the crew started brewing. But then, one character dies, another kills himself and a third leaves on a boat. It's like the movie was deliberately going out of its way to remain mediocre.
And don't use terms like "hadopelagic" and expect that to be a sudden eye-opener for the audience when you haven't explained to them what it means.