This review is "ok" except for the persistent referencing to the story as a "western" in trying to describe the overall story/theme - this is a horrible mangling of genre and first impressions for anyone reading a review to get an initial feel for a book/story. (Unless you really like westerns and prefer to have everything favorable related to you in terms of a good western.) The "simply" in the first sentence should be removed, maybe replaced with "similar to". It is NOT "simply a "western"". And ditch the sappy "sunset" line. The story wraps with a fine fade-to-black for the narrator.
The Dark Knight Returns is quintessential reading for anyone who has any like of: comic books, graphic novels, superheroes, fiction, fantasy, similar movies/TV shows, or the Batman.