"Good readers are also highly evaluative of the texts, deciding whether a text is interesting or the arguments made in it are credible. They make evaluations of the style of the text (e.g., the quality of the writing), as well as its content." (Pressley, M., 2002, During Reading, para. 6)
A critique is an evaluation of a given text. It's purpose is to express judgement about the quality of the craft and/or content a text.