What are differences in the presentation of Kurtz in Heart of Darkness by J. Conrad and in the movie Apocalypse Now by F. Coppola?

I think that there are some significant differences in the
manner in which Kurtz is shown in Coppola's film and Conrad's book.  One difference is
that Kurtz dies on the journey back in the book, while in the film, Kurtz does not leave
his compound upon Willard's arrival.  At the same time, Kurtz seems to die of modern
causes in the book, while he is clearly killed in Coppola's film at the hands of
Willard. Another change would be the level of brutality that Kurtz displays in the
film.  While the book shows him to be violent, the film shows this to another level.
Both depictions are savage, but I think that the film shows it to a far greater level. 
Finally, I think that Kurtz is shown as sick and ill in the book, while in the film this
dimension is not as explored.