What is a critical analysis?

A critical analysis is a description of what you, the reader, understand from the text. This shouldn't be from context you have researched or analysis of hypothesis posed by secondary critics, rather it is your analysis of the language, tone and structure of the text and what all of these together mean for the text. What message do they convey? What is the author trying to tell us? Why has she/he used short chapters? What is the significance of repetition in a chapter? And so on.