Hamlet, Act One.

Tragedy begins to be established in Hamlet's act one by the old King Hamlet being poisoned by his own brother.  This creates a position in which the villain is in charge of everything, and essentially winning.
Hamlet Jr is already somewhat coming down from being in his prime.  He was previously swanning around at university, getting his education, until the tragic demise of his father, then the wedding two months later of his mother to his uncle, the now King of Denmark.  Hamlet Jr considers this incestual, and is really rather angry about it all.
As the act moved on, the character of Hamlet Jr developed into a man we are rather confused by.  He begins relatively normally, and at that point we are sympathetic towards him and understanding of his plight.  Then he meets the ghost of his dead dad, has a chat with him, and, on hearing that his uncle/stepdad/king thing killed Hamlet Sr, he decides to pretend to be mad.
Um, what?
So, let me get this straight.
Your dad got killed by your uncle, who then started, in your opinion, to have an incestuous relationship with your ma, and you AREN'T going to go downstairs, where he's lying there a bit drunk, and chop his head off with your great big sword??
The character of Hamlet Jr here is being developed as the tragic hero, but one that we just don't understand at the moment.  He makes odd decisions and swears his soldiers to secrecy on the ONE thing that could help him, literally, get away with murder.
A tragic element already being portrayed is that of conflict in Ophelia.  She seems to be pretty mad over Hamlet Jr, but her brother and father are warning her away from him to the point of forbidding her from having anything to do with him.  So what does she do?