In his opening speech, we find Richard playing psychological games to try to convince himself that he is not alone. (He appears to be courting insanity when he does this, but that is apparently not of great concern to him.) Richard considers his isolation and tries to find ways to re-think its emptiness: "I have been studying how I may compare / This prison where I live unto the world; / And, for because the world is populous / And here is not a creature but myself / I cannot do it. Yet I'll hammer it out . . ." (1-5). This speech--along with much else that Richard says in this scene--can been read as a foreshadowing of the monologues Shakespeare will later write for Hamlet, another imprisoned intellect wandering in a gloomy castle and speculating on the nature of life, death, and identity. Hamlet, to whom Denmark seems as much a prison as Richard's literal jail cell, laments to his friends, "O God, I could be bounded in a nutshell, and count myself a king of infinite space -- were it not that I have bad dreams" (Hamlet, II.iii.243-256).
The imprisoned Richard tries several ideas out on himself: perhaps he will pretend that his own thoughts are people, and thus populate his prison. Then again, perhaps he himself is more than one person, for so he feels himself to be: "[P]lay I in one person many people, / And none contented. Sometimes am I king, / Then treasons make me wish myself a beggar . . . / Then am I king'd again, and by and by / Think that I am unking'd by Bolingbroke, / And straight am nothing" (31-38).
This series of identity shifts ends with Richard imagining himself as "nothing": "Nor I, not any man that but man is, / With nothing shall be pleas'd, till he be eas'd / With being nothing" (39-41). Richard's syntax is obscure, but his general idea is clear: he tends strongly towards nihilism, the idea that there is no purpose or value to existence. In some ways, this attitude has been visible in Richard from the beginning and has manifested itself in Richard's perpetual passivity and willingness to give in to despair. Nihilism is very modern concept, and its appearance in some of Shakespeare's dark-tempered protagonists is part of what makes critics see him as being such a prophetic writer: he is "modern" before his time. (The play in which this idea will come to its fullest fruition is, of course, Hamlet.)
A more literal "nothing"-ness arrives at Richard's cell soon after his metaphysical musings, in the form of Exton and the other murderers. The death scene is surprisingly short; murdered kings in Shakespeare's plays often get long and poignant speeches between their stabbing and their death, but Richard barely has time to curse Exton grimly for his deed and to bid farewell to the living world: "Mount, mount, my soul! thy seat is up on high, / While my gross flesh sinks downward, here to die" (111-112).
King Henry's mixed reaction to Exton's news in Act V, scene vi suggests that he realizes his own hypocrisy and feelings of guilt for Richard's death. His words to Exton demonstrate this extraordinary ambivalence: "They love not poison that do poison need, / Nor do I thee. Though I did wish him dead, / I hate the murtherer, love him murthered" (V.vi.38-40). Henry tries to lay the burden of guilt upon Exton, condemning him to wander "[w]ith Cain" throughout the world; but he is well aware of his own complicity in Richard's death, as is clear when he says to his court, "Lords, I protest my soul is full of woe / That blood should sprinkle me to make me grow" (45-6). However, the deed has been done, and the guilt of Richard's murder weighs heavily on Henry from almost the first moment of his reign. This guilt, and the pledge Henry makes to take a pilgrimage to "the Holy Land" (49), remain hanging in the air as the play concludes; they are the seeds of plot threads that will be worked out in the remaining three plays of the tetralogy.