Early in the play, Hamlet’s mood is dark and depressed, but when he’s given the task of avenging his father’s ghost, his desire to find out the truth gives him a sense of urgency and purpose. As the play progresses, and he fails to find a satisfactory way to correct the problem, he becomes increasingly frustrated, lashing out more impulsively, ruthlessly, and recklessly, until the final catastrophe. Thus we could say that the tone of the play, meaning the author’s attitude toward the events, seems like its going to be optimistic in the beginning of the play (when it seems like justice could be achieved), but bleaker as the play moves on, and it seems like achieving justice or redemption in a situation like this is impossible.
Hamlet makes passionate and intelligent attempts to understand himself and his situation, only to end up confused, disappointed or disgusted by what he encounters. The world of the play is both more terrible and more mysterious than its characters are capable of grasping. Initially Hamlet considers himself above the other characters, and his nimble wordplay, often at the expense of less verbally adept characters, gives the early scenes a playful tone, even as Hamlet is grieving his father. However, once Hamlet erroneously kills Polonius instead of Claudius, and learns that Claudius has ordered his execution, Hamlet realizes even he is not exempt from the malevolent forces of fate. The tone turns dark and brooding as Hamlet comes to terms with his own dark nature and resigns himself to committing more murders, in his killing of Rosencrantz, Guildenstern, and finally Laertes and Claudius.
The many secrets in Hamlet create an atmosphere of mystery and conspiracy. Claudius is tortured by the guilty secret of his brother’s murder. Polonius sends Reynaldo to spy on his son Laertes, and spies on Hamlet himself. The Ghost hints that Gertrude and Claudius may have been having an affair. The songs Ophelia sings in her madness seem to reveal that her relationship with Hamlet is sexual. Hamlet demands that Horatio, Marcellus and later Gertrude promise to keep secret that he is only pretending to be mad. Rosencrantz and Guildenstern try to hide from Hamlet that they were summoned to Elsinore. That we never learn the truth about most of these secrets encourages us to share in Hamlet’s frustration: like him, we suspect that terrible things are being kept from us. As the audience, we, too, are never certain to what degree Hamlet is acting insane as a strategy, and to what degree he has actually succumbed to mental illness. All these secrets and misunderstandings lead to a tone of distrust and insecurity, where the audience is constantly wondering what, if anything, to believe.
Hamlet dwells obsessively on sickness and decay, which keeps death at the forefront of the audience’s minds and sets a tone of disgust and despair. We encounter not one but two decaying bodies: Yorick’s skull (IV.i.) is the most famous prop in theatrical history, and after gruesomely dragging Polonius’s body offstage, Hamlet tells Claudius that “within this month you shall nose him as you go up the stairs into the lobby” (IV.iii.). Several characters suggest that Hamlet is mentally ill, and he himself admits that his “wit’s diseased” (III.ii). Even when the play’s characters are not talking about literal illness and decomposition, they tend to fall back on imagery of sickness and decay. Marcellus declares that “something is rotten in the state of Denmark” (I.iv.). Claudius says that his murder “is rank: it smells to heaven” (III.iii.) and Gertrude sees “black and grievèd spots” on her soul (III.iv.). Hamlet’s fixation on sickness and decay creates a sense that the entire world of the play is corrupt and doomed.
For a tragedy, Hamlet has an unusual number of comic scenes and characters, and the play’s black humor adds complexity and ambiguity to its tone. For much of the play Hamlet makes fun of Polonius, and we are encouraged to laugh with him at the old man, but when Hamlet murders Polonius we are horrified that Hamlet continues to make fun: “This councillor/Is now most still, most secret and most grave, / Who was in life a foolish, prating knave” (III.iv.). We are also encouraged to laugh at Hamlet in his worst moments. When he leaps into Ophelia’s grave, Hamlet declares his love for Ophelia in terms which we can only find silly: “Forty thousand brothers / Could not with all their quantity of love / Make up my sum. What wilt thou do for her? […] eat a crocodile?” (V.i.). The humor here is uncomfortable, because Hamlet’s behavior is cruelly inappropriate. This painful humor reinforces the play’s despairing tone, but it also creates complexity, because it distances us from Hamlet’s suffering and asks us to question how seriously we should take him.