I think it is important to remember that Poe is described as a "Dark Romantic," which is a kind of school of thought within Romanticism at large but with some notable differences to the main Romantic authors. Dark Romantics such as Poe had a view of the world that emerged from the mystical and the melancholy aspects of Puritan thought. Themes such as the conflict between good and evil, the psychological effects of guilt and sin and the madness in the human psyche were explored. The writings of Poe were all about showing humanity for what it really is - warts and all, removing the masks of social respectability that we often wear and exposing the depths of evil that humanity is capable of.
When we bear this in mind, therefore, this perspective becomes helpful in identifying the "Dark Romantic" elements in this excellent yet terrifying short story. Clearly, the narrator of this piece observes the troubling madness of Roderick and what he sees asks harsh questions about what Roderick has done in terms of interring the body (still living) of his sister. It also asks questions about the hereditary nature of curses, evil and madness and how they can dog families for centuries.