Which was better?
I personally enjoyed the movie better because it brought a lot more emotion with it. You could really see how intense the training and war was.
How the book depicted the theme
The book was full of stories about the war and really showed Chris Kyle's bravery. That being said, the theme overall was patriotism which Chris Kyle indefinitely showed by fighting for our country.
How did the movie adapt the theme of the book?
The movie adapted the theme of patriotism by showing the honor and bravery of Chris Kyle as he served our country overseas. It shows how united our nation can become when a veteran is killed.
How did the movie adapt the relationship between the characters?
The movie depicted Chris Kyle's PTSD after he returned home and it really changed him. It also hurt the relationship between him and his family.
Protagonist in the book vs. Protagonist in the movie
In the book, the perspective is all from Chris himself and it is himself telling all the stories from the war and from his childhood. In the movie, it shows Chris Kyle actually performing in these stories.