What is the difference between allegory and extended metaphor?
Allegory and extended metaphor are similar concepts, but they are not exactly the same.
An allegory is a literary device in which characters or events in a story represent abstract qualities or ideas and carry a symbolic meaning. In allegory, the author does not tell us that one thing is another but invites the readers to interpret the symbolic layers in the story.
With extended metaphor, the author makes a detailed comparison between two unrelated things, typically by stating that one thing is another. In other words, there is no hidden meaning behind the characters or events.