Expert Answers
amy-lepore eNotes educator| Certified Educator

To add to your previous list:

Ambition (Claudius, Hamlet, Polonius, Ophelia)

Family Relationships (Ophelia, Laertes, Polonius/ Hamlet, Gertrude, Claudius, King Hamlet)

Madness (Hamlet, Ophelia)

Appearances vs. Reality (Hamlet "acts" crazy; King Hamlet as the ghost, Claudius as innocent heir to throne, Gertrude as ally or innocent wife of a murderer, Rosencrantz and Guildenstern as friends to Hamlet)

 

playsthething eNotes educator| Certified Educator

This question has been asked and answered several times.  Follow the link:  http://www.enotes.com/hamlet/group/search?q=theme

A short list:

Revenge - major theme - similar to Roman tragedies in which a principal character is driven by revenge.

Mortality - purpose in life (Hamlet's "to be or not to be" speech is the center of this.  Ophelia's suicide also figures in this theme.

Friendship - Hamlet & Laertes, Hamlet & Ophelia, Rosencrantz & Guildenstern, etc.