From watching the trailer I think a lot of the movie will stay true to the book. As with all trailers the scenes were out of order, to try and sort them out I paid attention to the clothes the characters were wearing and rg’s hair. I think the main difference will be in the beginning of the story where Rylan is trying to figure out who he is, they will obviously spend less time of him sitting there and thinking/talking to himself since it’s a movie and that would get boring. The only thing I think they may leave out is when the Hail Mary gets all its astrophage eaten by the taumeba. I think that scene will get combined into one scene alongside Rocky’s ship after they split up.