The action is similar, but out of order. The endings are different, but I liked the movie's ending much better. In fact, it contains one of my favorite lines from a movie. I won't spoil the surprise. Sam Peckinpah directed and it is predictably, yet appropriately, violent.
German authors tend to philosophize, but the movie has cut that to an acceptable level.
I feel that this is one of the best war movies ever. It was released too near the end of the Vietnam War to be accepted for the great movie it is.