The Martian is often described as Cast Away in space. I agree. It presents the incredible task of surviving, alone, on Mars. Just like Tom Hanks surviving on the island.
But improvising life on Mars is several degrees more complex than on that island. This is why the main character in The Martian has to be a very, very very smart guy, a little too MacGyver to be honest. Imagine Apollo 13, the movie, when NASA focuses on converting ship scraps into an oxygen filter, but for the entire duration of the movie, it was done mostly by one guy.
80% of the book, Mark Watney is in dire straights. Always facing high odds of dying. This is why the book is so compelling. It sucks your soul, making you wonder at night “how he can pull this off now?”. Watney must have a clear state of mind all the time. I understand that it would not make any sense to write a book about a normal guy that gets lost on Mars and dies after the first disaster. But Watney is too much the perfect guy to be lost in spaceace.
The book sometimes abuses the technical description of the solution. It could be shorter by a bit. However, and this is not a small achievement, there are at least 2 moments when I was crying due to the narration and climax feeling.
It will become a movie directed by Ridley Scott and started by Matt Damon. I will see the movie for sure.