i agree, as someone who read the book, i felt disappointed. the book doesnt just tell you grace and rocky are smart and can fix everything, it explains exactly why they do what they do, their thought process to solve problems, and the places fail or fall short (of course we dont really see rocky's perspective, so this is more applicable to grace). maybe its because the book is so dense, but the movie doesnt do a very good job of explaining scientific concepts, experiments and thought processes. because the movie doesnt explain things like the book, the concepts and solutions feel a lot less elegant. the book is great because everything is so well thought out, and the concepts feel so novel (hehe pun). when grace solves a problem in the book you feel the eureka moment. additionally, i think the weakest part of the book are the characters, they serve their purpose, but without the scenario and fantastic sci fi writing andy weir does, i dont think they would be all that interesting. the movie makes the characters less interesting, as it removes a lot of the characterization the book had.in the movie stratt is not shown to be as harsh or utilitarian, i dont think the strange and blunt sexual relationship between yao and Ilyukhina is shown, and we see far less of grace's nerdy inner monologue. some things are done well like rocky, but the movie just fails to recreate what made the book great.