Partly the lower rating is because a novelized game of Risk isn't really my thing, and also because the writing in this installment of the Ender/Shadow series felt a bit sloppier written than Card's usual. There was a lot of repetition of information, sloppy exposition and the like, which could have been done more gracefully. Also, it seemed (having read Ender's Shadow just before this book) that Card decided to make some tweaks to his characterization of Bean and Petra, which were not necessarily consistent with the way they'd been portrayed in previous books. The narrator tells us, for example, that Bean and Petra were friends and got alone very well during the final test of Ender's Game (I am trying not to be spoilery), but that's not really how their interactions came across at all. This change from on high made most of Bean's actions seem rather baffling, and I kept trying (in vain) to reconcile the Bean of Ender's Shadow with the Bean of this novel.