Both Hamlet (left) and Claudius (right) are fixated on avenging their fathers death by murdering the killers that ended their fathers life. This is a major theme in the play because these men spend a whole of the play trying to get revenge. Though they each have different methods of going about this.
Revenge
Corrupted
Gertrude is thought to be corrupt for a reason. As soon as the king she was married to died, she moved on to his brother who happened now to be king. She never ceased to be queen, and perhaps that is what she was after. She hungers for power, and so plays the deadly game of thrones. This shows how she is corrupted.
Though as he appears and try's to be a good father Polonius's personality comes off as Self-assured, cynical, self-centered, a flatterer, long-winded, sly, devious, false, shrewd, immoral and manipulative
Appearance V.S Reality
Death
Ophelia kills herself because the fate of Denmark is placed on her shoulders when she is asked to more or less spy on Hamlet, her father has been murdered by Hamlet, from the confusion created by her father and brother with regard to the meaning of love, and her suicide is even an act of revenge.
Political
King Hamlet was the ruler of Denmark. He was murdered by his brother to earn the crown. This theme was very important to the play because there were kings and queens which had caused a lot of problems such as murder.
Hamlet was a story with many themes. A few being Death. Revenge, Politics, and Corruption. This play was a tragedy with many deaths and a lot of sorrow.