In this first act of Hamlet, several themes arise and although it is hard to discern which will be reoccuring and which will be momentary, they are still worthy of mention. The gloomy and spooky atmosphere of the play is set with the appearence of the ghost in the first scene, which begins the characters' relationship with the super natural and the theme of death and what that may provoke in people. While death is something that is constantly contemplated in the play overall, for example, Hamlet's talk of suicide, I feel that the main theme of the play would be retribution or revenge. Throughout the first act, everything seems a bit odd for Hamlet and once he has encountered the ghost of his murdered father his path has been set for him, attain revenge for the death of his father. For the rest of the play, this will be the central theme for the title character making it the most important theme in the play.
This theme gets the reader to start contemplating on whether this quest for revenge is something that Hamlet should pursue, and what toll will the act of taking revenge have on Hamlet and the other characters if he does follow through with his father's request. While other themes, such as misogyny and death are pondered in the play, it is revenge and what revenge means that takes the cake as the most important and central theme of Hamlet.