In Hamlet by William Shakespeare there are many key points of interest in the story of Hamlet.
One key point comes from a quote from the main character Hamlet. The quote is “To be or not to be that is the question.” This shows the internal moral and the difficulty one has overcoming such a conflict.
A key theme is to be thankful for what you have while you still have it. This is shown quite a few times in the story. The major time this is mentioned is with Hamlet and Ophelia falling in love. Hamlet goes to school in London, and Ophelia becomes depressed from Hamlet killing her father and then him leaving. Ophelia then drowns in the river and upon her funeral Hamlet returns. As Hamlet realizes that it is Ophelia's funeral he proclaims his love for her and regrets that he didn't marry her.

Another key theme is to not hesitate to long about a decision. It shows this theme at the end of the book. (I'm not going to go into details about it; you're going to have to read the book to find out).
The book in general is defiantly a tragedy, with a depressing tone and the characters thoughts are mainly dark and treacherous. In particular, Hamlet, the main character, has thoughts that are very dark and treacherous. Even though it only shows one side of his mind it shows him to be real.
Since it is written as a play there is very little said about the setting except the fact that it is in a castle in Denmark in the 1500's.
Hamlet was written in the beginning of Shakespeare's tragedy period. Most consider it the first major tragedy he wrote, where as before he normally wrote comedies.
In conclusion, Hamlet is a story with a tragic plot that has many twists, turns, and surprises.