What can you say about the narrator in Heart of Darkness?
One of the fascinating ways that Conrad set up the story is the way that the narrator or narrators provide several different viewpoints on the story and basically leave many opportunities for different interpretations of things by the reader. We essentially get the story from three narrators, the majority of it from Charlie Marlow but also from the narrator that gives the reader the description of Charlie as well as the pseudo-narrator in the form of Conrad who, as the author, is careful to allow the reader to know certain things but leave others to the imagination.
And beyond the interpretations left open by the shifting narrative point of view, there is a great deal about the tale that invites the reader to interpret or consider what the deeper meanings are in the story. Even the title prompts the reader to consider the inner workings of the characters and what they symbolize.