Wearing No Shoes Symbol
Tradtionally, Ophelia has always been portrayed has having wild, unkempt hair, and going shoeless, both of which are considered symbols of madness in the original play. In this cinematic version, Hamlet also begins to go about Elsinore without shoes, which is a symbol of his own descent into "madness", or at least, it is his interpretation of what this symbolizes, as he is using this symbolism to construct the appearance of his own mental unravelling.
Madness Motif
One of the key motifs in the movie is that of madness, and it is pivotal to the plot in that it is displayed both genuinely in Ophelia, and as a pretense by Hamlet. Ophelia descends into madness after the death of her father, and ultimately drowns, probably committing suicide although this is never definitively stated, just implied.
Hamlet decides that his best defense against his murderous uncle is to feign madness, which would give him a shield to hide behind whilst trying to find out if Claudius really did murder his father as the ghost has suggested. There are also several explanations given for madness in the story, the chief of which being madness induced by love sickness - literally, going mad with love.
Although he is feigning his madness, it is hard for the audience to tell whether his madness is entirely his own creation at times, for example, as he sees Ophelia's funeral procession, and is grief stricken; this seems genuine, which makes it difficult to tell how genuine his prior demonstrations of madness have been.
Play Allegory
When the troop of actors perform the play Murder at Gonzaga, it is intended to be an allegory of the murder of Hamlet's father; the murder is committed by pouring acid into the ear of the king, which is of course how King Hamlet was killed as well. Hamlet is aware of the allegorical suggestion of the play which is why he selects it for the troop to perform, and watches Claudius' reaction to it.
Yorick's Skull Symbol
Hamlet sees Yorick's skull in the graveyard as he watches two gravediggers digging a grave that he is as yet unaware is intended for Ophelia's body. He speaks to the skull as if he were speaking to Yorick himself; Yorick was a popular court jester whom Hamlet remembers well from his childhood. Yorick symbolizes this time in his life when he was carefree and happy, and the skull symbolizes the inevitability of death, making Hamlet think about his own mortality.
Ears Symbol
The ears are a symbol of dishonesty throughout the film. King Hamlet is murdered by poison being poured into his ears, which symbolizes how poisonous and deadly listening to dishonesty can be. When Hamlet declares that he was murdered, he states that "the whole ear of Denmark was poisoned by dishonesty."
