I think that "The Cask of Amontillado" is interesting because it is based on a true story. Poe read a newspaper article about a body found walled up in a crypt in Italy, and that seems to have gotten his wheels turning. I wonder how true his version was?
I guess I'll state the obvious point of comparison--since they're written by the same author, they share a similar diction and style in the actual writing. All the other elements mentioned above are more significant, but reading these two Poe selections--as well as any others, actually--his particular diction (word choice, vocabulary) is recognizable. That speaks of similarity and comparison.
Other editors have summed up the key similarities between these two masterful gothic tales. The major similarity is of course Poe's masterful use of the unreliable narrator. This point of view takes a first person narrative but key to its success is the way in which the attentive reader is not entirely convinced by what is written and begins...
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