I'll keep this brief, Richard Bachman (a pseudonym of Stephen King) has made something really great here. The premise of the book is annually, 100 teenagers entered a competition called "The Long Walk" where they have to walk literally non-stop until only one person remaining. The winner gets to have anything they want. It's a very simple premise and it somehow made Hunger Games looks like Disneyland. The slow descent into madness and insanity are clearly shown step by step, the changes in the characters from when they began were shown gradually.
This is truly a dark tale, sometimes even depressing. The author's prose was great and descriptive. The fatigue, the pain, and the gradual changes in the characters can be felt from the writing. Not gonna lie, at one point, I felt my feet get tired from reading. It's a very compelling story, I finished reading this in one day.
The minor cons I had on the book was even though this is a really short book, there are still some parts that I felt goes on a bit longer than necessary during the first half of the book. Also, the ending was too abrupt and a bit too ambiguous. There are a lot of great fan theories on the ending though, so if you feel disappointed by it, I think one of this theory can put more closure on the reader.