Andy Weir (the author of the book) has a Producer AND Writer credit on the movie and had some say what bits to take out and what to change.
The changes worked really well for the movie, they changed some subtle bits, compressed others but the emotional core is still there and Ryan Gosling makes it work - the dude can act.
The changes worked really well for the movie, they changed some subtle bits, compressed others but the emotional core is still there and Ryan Gosling makes it work - the dude can act.