Polonius dies in Act 3. Ophelia dies offstage in Act 4; Rosencrantz and Guildenstern die offstage sometime after Act 4. Hamlet, Claudius, Gertrude and Laertes all die in Act 5.
This is Ophelia's madscene. It establishes that Ophelia has gone over the edge but also has the more important action in which Laertes confronts Claudius, and is persuaded by him to take his revenge against the person who really killed Polonius, which would be Hamlet. This scene provides the basis on which the final denouement is based.
In Act 5 of Hamlet, there are several allusions to classical mythology, such as references to Hercules and his labors. There are also allusions to biblical imagery, such as the comparison of Ophelia to a saint in her burial. Additionally, there are references to historical figures, like Julius Caesar, in the discussion of the grandeur of Alexander the Great.
The clowns are just grave diggers (everyday civilian) who are digging Ophelia's grave at the time.
There's no scene where Hamlet gives Ophelia gifts. We understand that he has, because of the 'Nunnery Scene,' in Act 3, Scene 1, where Ophelia returns Hamlet's gifts. In that scene, she says "My lord, I have remembrances of yours, That I have longed long to redeliver; I pray you, now receive them." By the way, "remembrances" are keepsakes, sentimental gifts, like a flower for example.
By Act 5, Hamlet knows just about everything he needs to know. He reports to Horatio that he discovered the secret orders given to Rosencrantz and Guildenstern which proved that the King was trying to kill Hamlet. He does not yet know about Laertes' complicity in this, but doesn't try to find out either. When he finds out that Ophelia is dead, he does not inquire after the details of her death. He has made a decision to go with the flow ("There's a special providence in the fall of a sparrow.")
Hamlet's friend Horatio was most loyal to him. Furthermore, in Act 1, scene 5, Hamlet makes Horatio and Marcellus swear loyalty to him and to never reveal what they have witnessed in the woods and Hamlet's interaction with his father's ghost.
The poisoned tip of Laertes' blade cuts Hamlet in their duel in Act V; thus Laertes is the direct cause of Hamlet's death.
The beginning plot of Hamlet ended in the last scene of Act 5.
Hamlet doesn't kill the king in Act 4. He kills him in Act 5. Hamlet doesn't kill anyone in Act 4 and in fact he is offstage for most of the Act.Hamlet doesn't kill the king in Act 4. He kills him in Act 5. He doesn't kill anyone in Act 4 and is in fact offstage for most of the Act.
The Ghost, in Hamlet, Act 1 Scene 5
The reason for Ophelia's madness, which is introduced in Act 4 Scene 5, is never directly stated in Hamlet. Probably causes include being instructed by her father and brother to stop seeing Hamlet, with whom she had been romantically involved. After breaking up with him, she watches him apparently go mad, and bears the brunt of one of his angry outbursts. Shortly after, her father Polonius is murdered by Hamlet himself, leaving her with no family in the area, as her brother Laertes is at school in France. The combination of these stressful and painful situations most likely leads Ophelia into madness. Ophelia's madness comes from not only being publicly humiliated by Hamlet but also hearing about how Hamlet murdered her father.