The ends of “Heart or Darkness” and “Apocalypse Now” are dramatically different and change the whole meaning of the story. The first is in the Movie. Marlow’s friend gets his head chopped off. In the book, he has no such friend. Marlow arrives at the boat by himself. This changes the movie dramatically because this scene is used for drama and emotion. You, as the viewer, are supposed to feel for the man. In the book it totally bypasses this segment and sticks to telling the story rather than just shoeing the story, i. e. he book offers more analysis and the movie more action.
I see the contrast as thought and contemplation vs. action and muscle. The second difference is, in the movie, Marlow never tries to take Kurtz he just leaves. In the book, he tries but Kurtz dies. This is a huge difference. This detail changes how one would analyze Marlow. His demeanor obviously changes if he tries to save someone or leaves him,( or kills him). The third, and largest, Kurtz is brutally murdered in the movie. In fact, we can even see his limbs being chopped off, as the buffalo is too; utterly horrid.
In the book Kurtz just dies of malaria because he is so weak. Let’s weigh these two events. Hacked to death with a machete or dying of lost strength. Huge events that can shape the way the reader could be affected by the book. All in all, as I said before, it seems in the book, Conrad sticks to a more analytical side of the character of the characters, while Coppola seeks to shock the viewer into understanding the horrible events. The book wants you to think for yourself and figure out each character and the movie blatantly tells you. Show vs. tell.