I was a little cautious going into reading this because people had said it’s very “science heavy” and I was worried I would get bored. I am SO glad I decided to read it anyway. I liked the Martian but I think this one is much more my cup of tea. 
I was unsure of the narrative at first but as the book went on the narrative became one of my favorite parts. 
My favorite part has to be Rocky. What a perfect friend for the protagonist and I think one that really added to the quality of the story. 
Weir does use a lot of science in the book but everything is explained in a digestible-for-non-scientists type of way. But the scientific elements really make the story feel believable, like it could really happen. 
Weir does an excellent job of keeping the reader engaged while sprinkling in humor and warm fuzzy moments. 
An exceptional book, definitely my favorite of Weir. Also one I will recommend for years to come. 
Also, I thought the ending was absolutely PERFECT.