Movie adaptation - No Country for Old Men

Given that I recently read and reviewed No Country for Old Men, I decided to rent the DVD of the film adaptation.  Made by the Coen brothers, the movie is about as faithful a translation of a book as I've seen since for quite a while, with the exception of the ending.  In most scenes the dialogue is word for word from the book and the casting is pretty good.  I'm not sure though how much sense the movie would make to those watching it who had never read the book, as the narrative often lacked context, with scenes involving characters that hadn't been introduced or it clear why they were included.  The movie did fill in one gap missing in the book, but missed a chunk out from the book's ending.  I felt the novel had a relatively weak ending, but movie more so.  I'll try and write the next bit without giving spoilers, but will hopefully make sense to those who have read the book and watched the movie.  If it had stopped at the point where Chigurh walked out the house, that would have worked okay, but to stop where it did seemed to cut things off mid-section and makes little sense for anyone who hasn't read the book as it does not explain who was driving the car or why the accident occured.  Anyway, always interesting to see how a book is adapted for the big screen.  The book was better, but the movie was above average.