To what degree do Claudius, Gertrude and Hamlet each receive their "just rewards" in Shakespeare's Hamlet?
In Shakespeare's Hamlet, it would seem that several of the primary characters are "punished" by the end of the play.
Claudius is an easy case to support: he has murdered his own brother in order to become king. Shocking Elizabethan sensibilities, he has married his sister-in-law, which is considered an incestuous act, and he plots to kill Hamlet when he believes that Hamlet is suspicious of Claudius' part in Old Hamlet's death. Of course, his further attempts to kill Hamlet during the "sword play," not only bring about the death of everyone involved, including Laertes, but ultimately bring about Claudius' death as well.
Hamlet is often considered guilty of indecision: he delays in killing his father's murderer. I find myself sympathetic to Hamlet's inability to act because he is not sure that the ghost is really his father, and worries that if he kills the King (a mortal sin), he will go to hell. However, it is generally felt that Hamlet's failure to act brings about the death of everyone else, including himself.
Gertrude is one that I don't believe gets her just rewards. She does marry her brother-in-law (once again, incest in the minds of the Elizabethan audience), but she is a woman in a male-dominated society. She provides for herself in marrying her husband's brother, and is also able to keep an eye on her son, and ostensibly to protect his right to the throne, as Claudius has no heir. When she learns her new husband is a murderer, she is sharp enough to keep the knowledge to herself without giving Claudius the idea that he has been found out: she does this mostly to protect Hamlet, not herself. With few options open to her, when her husband dies, I believe she does what she can to protect herself, her future, and most importantly, her son. It is Claudius' murderous actions that ultimately bring about the death of most of the members of the Danish court.