This paper argues that, while Hamlet may have idealistic motives for seeking to avenge his father, he inevitably becomes mired in the corruption unleashed by Claudius in the killing of his brother and the committing of adultery with his brother's wife. As for responsibility, that becomes a question of free will versus determinism and fate. Interestingly, Hamlet struggles hard to shift the responsibility onto himself (most famously in his "To be or not to be" soliloquy) but the presence of a belief in a divine being makes that difficult to understand logically, even if we accept it emotionally.
