This film was the most faithful, to the book, of any I have ever seen. It is based on one of Louis L'amour's early western novels, and the first to be made into a film. Aside from Vittorio wearing war paint all the time, the only part which was not really faithful to the book was the final battle where the stereotypical Hollywood Indian battle was substituted for the manner in which Apaches actually fought.
Louis L'amour was the most successful western novelist in history, having sold more than a quarter of a billion books before his death in 1988. Reading the book, Hondo, I often suspected it had been written with John Wayne in mind as Hondo Lane. I cannot picture Glenn Ford as Hondo, as was originally planed.
Much of the dialog was taken directly from the book although much was omitted, and every significant character made it from the book to the film. The only significant negatives were: 1) the fact that the story was condensed into 83 minutes instead of the 100 to 120 minutes, which would have permitted development of some of the minor characters; and 2) the apparent absence of a competent director. Think how much better it might have been if John Ford had directed it. Actually, both my complaints probably boil down to the same thing.