The comments on this film seem evenly distributed between favor and disfavor. At this date, I can't understand why anyone would not like it, but that's me. I first saw it in 1967, while I was in college. I loved it, and went so far as to locate and purchase the book(s) from which it was adapted. And that was before the internet, and Amazon, and Bookfinder. One of the books I didn't manage to get until I got to London. Reading it, I was amazed to realize that the film actually includes remnants of every story in the book(s): when, for example, Alphonso opens a door to find a bewigged scholar interrupted while declaiming "...Then the first skeleton tore out his own arm-bone and began hitting me with it..."-the whole story is there in the book, i.e., what the skeletons were doing there in the first place. The books, Manuscript Found At Saragossa and the New Decameron, are rightly considered Literary Treasures of Poland, along the lines of Notre-Dame á Paris in France, War and Peace in Russia, or Moby-Dick here. It's about stories and storytelling.
By the end of the film, to say the least, the viewer has been presented with a convincing picture of sixteenth-century Europe from different angles, and it's safe to say that no other film, before or since, in color or Black-and-white, has done it better.