Well, I finished reading The Martian last night. Thoroughly enjoyable. There were, indeed, many twists and turns past the mid-way point of Andy Weir’s novel, but none of those turns took us beyond the point of plausibility. Whether one believes what one is reading as he or she approaches the end of the story is another question, but the story is plausible. Weir’s technical inventiveness and his sense of fun and adventure never fails. If the novel ever falls just a little short in some way, it may in its lack of character development among Weir’s supporting cast. The focus is on Mark Watney, which is right where it should be, but the people trying to help him–from Venkat at NASA to Commander Lewis in the Hermes–come off at times like stick figures. But this is only Weir’s first published novel (not counting two unpublished ones). If he stays in the game, he’ll get better at developing a character.
Besides, the attraction of The Martian is mostly in the kinds of problems it sets forth to be solved, not the people who solve them. NASA administrators, technicians, and flight crews tend to be introverts, not extroverts. They live and die within the life of the mind. Watney the engineer, as you may have guessed, is the exception to that generalization, and his personality is what makes The Martian such an exceptional read.