This Act has the following important aspects:
a- The gravediggers joking about death provides some comic relief just before the final scene of multiople deaths.  It also prepares us thematically for the play's outcome.

b- In Hamlet's easy familiarity with the gravediggers, as earlier with the players and pirates and with his less well-born college friends, we see the true gentility of one who, being "to the manner born," is able to forget his special aristocratic privileges and become "even-Christen" with all men of good will.  This contrasts Hamlet with Laertes, who always stands upon "ceremony."

c- When Hamlet offers to duel with laertes and then asks him his grievance, Laertes has the opportunity to explain himself honestly to Hamlet.  Laertes can then either accept their mutual love for Ophelia as reason for their reconciliation or attempt to revenge his father's death in an honorable duel to the death.  Laertes, however, is so angry that he continues to nurse his secret and ignoble revenge.  Claudius can easily use Hamlet's irrational behavior as a means of strengthening Laertes allegiance to himself and insuring the speedy enactment of their plan.
 

CONCLUDING COMMENT:

    Horatio has spoken of two kinds of deaths, "of accidental judgments, casual slaughters", and "of deaths put on by cunning and forced cause."

    The first type characterizes Hamlet, whose killings have all been accidental or casual.  The second type characterizes the "deep plots" of Claudius and Laertes, who have tried to shape their ends directly with the ironic result of punishing themselves and those most dear.

    Hamlet has allowed Providence to work itself out through him.  Claudius and Laertes have tried to shape their own destinies and for this they are punished.  As for Hamlet, the tension between earthly defeat and spiritual redemption is the reason for which Hamlet's death is truly a tragic.  For at the very moment when he has finally achieved a full "readiness" for a noble life to prove his royalty, his life is over.

    Oh, how time does pass.  It was just a few years ago when my poor Hamlet has left.  How I loved him so!  He was such a great person.  Not to mention, a very well-mannered and intelligent one.  We were such good friends.  He always seemed to confide in me, and me in him.  I remember when the poor kids' father died, how devastated he was.  As well as all the other events followed by that.  Such as the marriage between his mother, and uncle, the appearence of the ghost in which he learned the truth about his father's murder, Ophelia's death, etc....

    The poor little boy!  He just might have been seated beside me if it weren't for all the agony he went through.  I just wish things can be different.  Oh, how I do miss my dear friend Hamlet! However, I have to say, he was a very strong person, and fought to the end.  If that were me, I don't think I would have lasted as long as he did.  But, then again, Hamlet was always strong in that field, although he never showed it, and acted completely different.  I guess it just goes to show he truly was an amazing person.