The main difference between a feminist and a psychoanalytic reading of Conrad's Heart of Darkness is that the former focuses on the role of women and systematic gender oppression, while the latter would focus more on the subconscious workings of the mind of either a character or the author.
One possible feminist reading would examine the roles of the major female characters of the novel, namely Marlowe's Aunt, Kurtz's Intended, and Kurtz’s Black Mistress. Although twentieth century feminisms might have focused on the individual women in relationship to patriarchal oppression, more recent feminist criticism would be more likely to explore the connections between gender and colonial oppression, looking at the different ways in which both white and black women are excluded from centers of power. The two knitting women sit outside the office, and while Marlowe's Aunt helps him obtain his position through social connections, she is not actually employed by the company. Neither of the two women affiliated with Kurtz have independent stories, but rather simply function as supporting characters in Kurtz's story, both the prototypically European Intended who never hears the real truth about the "horror" of colonialism, and the colonized mistress.
A psychoanalytic reading of Conrad's Heart of Darkness would associate Africa with the primal Id, lying at the dark heart of the subconscious, as a place where Kurtz is stripped of civilized restraint. Europe and its "civilization" becomes the superego, the place of restraint, and internalization of social conventions and moral systems. Many psychoanalytic approaches to the work look at Kurtz almost as a projection of Marlowe's own conflicted nature.