A review is a description, critical analysis, and opinion on the quality, meaning, and significance of a book or movie, not a retelling. It should focus on purpose and content. It is a reaction paper in which strengths and weaknesses of the material are analyzed.
Reviews help others to decide weather they will like or dislike something. A good reviewer will be someone who understands the book, article, or movie they are reviewing. A good reviewer will also give facts to support their opinion.