Hamlet Character Development: Act 1

Hamlet is alone after Claudius and Gertrude exit right after he has just explained to Gertrude that he is truly grieving:

Oh, that this too, too sullied flesh would melt,

Thaw, and resolve itself into a dew,

Or that the Everlasting had not fixed

His canon 'gainst self-slaughter! O God, God! (1.2.133-136).

The soliloquy shows Hamlet's true feelings, and how he wishes he could commit suicide without sinning. Hamlet's character is clearly portrayed through his soliloquy and how he is truly grieving for his father, and is not acting like he believes some may be. It reveals that Hamlet is radical as he says, "Oh, that this too, too sullied flesh would melt," showing how he thinks the only method of his grieving is to kill himself. 

We also see more of Hamlet's character revealed when he is talking to Horatio about the King's drinking:

So oft it chances in particular men/That for some vicious mole of nature in them—/As in their birth (wherein they are not guilty,/Since nature cannot choose his origin),/By the o'ergrowth of some complexion,/Oft breaking down the pales and forts of reason,/Or by some habit that too much o'erleavens/The form of plausive manners—that these men,/Carrying, I say, the stamp of one defect,/Being nature’s livery or fortune’s star,/Their virtues else (be they as pure as grace,/As infinite as man may undergo)/Shall in the general censure take corruption/From that particular fault. (1.4.26-39). 

In this conversation we see how Hamlet feels about faults, and how he views them as negative things that can affect a person's life no matter how small and insignificant. Another aspect of Hamlet's character that gets revealed is his pessimism. He is very negative, and clearly doesn't see the positives of flaws and only the negatives. It sets a common tone with which Hamlet talks, and reveals how he is a negative grieving son.