What is the author's style in King of Shadows by Susan Cooper?

The trickiest part of the language may in fact be the actual interpretation of the interpolated Shakespearean text into the novel. However, the author places the Shakespearean text in for affect only. Nat explains the plot of A Midsummer Night's Dream throughout the novel, so it is not necessary for the reader to interpret Shakespeare's text. Those readers who are familiar with the plays already will find the interpolation fun, but not central the plot of the novel.