 At the beginning of the play, he struggles with whether, and how, to avenge the murder of his father, and struggles with his own sanity along the way.By the end of the tragedy, Hamlet has caused the deaths of Polonius, Laertes, Claudius, and Rosencrantz and Guildenstern, two acquaintances of his from childhood.He is also indirectly involved in the deaths of his love Ophelia (drowning) and of his mother Gertrude (poisoned by Claudius by mistake).