Rebecca Ferguson plays her character very intense, keeping one's attention to the story, and smoothing over the otherwise rather standard SF fare.
Visuals are good, the setting is not completely absurd, and I am now invested enough to want to know how this plays out.
However, i do not understand why simple common sense is wantonly abandoned. No way would Fergusson's engineer character climb down a 100 feet rope without any aid, a makeshift stepladder, securing ropes, anything! How does she think she's ever going to climb up again, by the strength of her hands ? Also, there is no way she loses her grip, falls 15 feet, and catches herself again, as shown for drama. This absurdity just kills my immersion.
Why would she fix the rope in the most inconvenient place above the middle of the lake, when i can see in the few seconds we are shown the scenery, that she could affix it above a structure she could actually stand upon once she's down.
None of that is important for the story, but it makes her character unbelievable, nobody could be that stupid, and breaks the empathic bond we want to have with her.
The scriptwriters should have to write "I will not make my characters act like the don't think 10 seconds ahead, and that are also physically impossible" 1000 times while clinging to a rope.