Part III of Hamlet

What is odd about the Ghost’s appearance to Hamlet in the Queen’s bedroom?

First, the purpose of the ghost is peculiar. Previously, he always comes with a purpose of either looking for or informing Hamlet. However, now he seems to be reminding Hamlet of his duty. This is happening while Hamlet chastises his mother for her actions. If anything, the Ghost should be happy with what his son is doing, since he is “revenging” the deeds of his mother by making her feel guilty. Also, Hamlet does not need a reminder about killing his stepfather. He is perhaps as motivated, if not more, to avenge his father’s murderer as his father is. Next, the visibility of the Ghost is strange. Earlier in the play, Bernardo and Francisco easily see him, for example. However, the Queen, the very wife of the dead Hamlet, is unable to see him.