We all live in a kind of continuous dream... 
 There are lot of dream like qualities to the writing nicely mirroring the events that takes place in Area X. Either it is a clever way of keeping the reader in a steady state of confusion with an unreliable narrator or its a tragic ploy of the storyline to maintain oddity of the nature of ecosystem with weird creatures. 
 The world is brilliantly detailed. It's creepy, its beautiful, grotesque and eerily act as a primary character in the story. There is no hint of time - the characters don't mention it (if its in current timeline or some centuries into future) though they talk about cellphones and televisions. The expedition doesn't allow modern technology and the narrator of this story, a biologist, is perfectly fine with it as she isn't much into communication and such. When the expedition arrives in Area X which is a continuously evolving ecosystem, they don't carry watches or compasses. It's interesting to note that the people don't have concept of time and are fully driven by what their new surrounding tell them. They cannot communicate with the outside world and are encouraged to alienate themselves even within the group; all in the name of uncluttered perception of what they were going to see and experience. It's interesting how its inherently contradicting to the group mentality that the "superiors" enforced by sending a bunch of them yet asking them to keep their thoughts and opinions private. The goal of their mission is ambiguous and they accept the abstract nature of the mission which begs the question - is it really an expedition that's completely isolated from outside or a huge experiment where the people are mere variables? 
 The narration is slow, exploratory and provides lots anecdotes from the narrator's personal life to prolong the wait for answers. It is frustrating at times when all you want is to know what exactly transpired but what you get to read is about the narrator's experience in college but it can be argued that it's her way of coping with the reality bending scene unfolding in front of her. She says over and over again that she is a biologist first - always has been and the events that takes place in the tower shakes her. However certain anecdotes the narrator shares are repetitive. It sort of jerks you away from a creepy mood setting which can get annoying in a narrative work like this. 
 The explanations for many things don't come in this book. The narrator spends time in evaluating the science behind an event and pushing her thoughts from her past thus disconnecting the reader from the eeriness of the event. It gets hard to get connected to that thought process because as a reader I want to know what is going on but since I am reading the story as narrated by someone else, I will have to go through her way of looking at things and reacting to it. This can be a let down for some people who find the narration too psychedelic and not fluid. 
 I enjoyed this book a lot and couldn't wait to finish it. Its written very well. Its really more a psychological thriller than horror or fantasy.