(MINOR SPOILERS; RECOMMEND LISTENING WITH NO CONTEXT)
You can expect a story that's "The Martian" meets "Interstellar" meets "Speaker for the Dead from the Enders Game series"
With that being said. I loved it! A more captivating story about interplanetary friendship than ET. Have never felt more attached to an alien lifeform, due to Weir's character writing for Rocky. The story has it's funny moments, but our protagonist, Ryland Grace, isn't nearly as witty or goofy as Weir's Mark Watney character. Rocky is definitely more of a comic relief due to the constant confusion of human nature and the amount of expression he manages to convey for having no facial expressions. A very interesting speculation as to what alien life could be like and how humans may learn to communicate/build relationships with them.
Whole heartedly hope to see Weir come up with a sequel.