At first, the one distinct thought this book gave me was, “What the...?” The topic of this book - an adolescent alien hunter searching for his parents' extraterrestrial killer - is somewhat of a departure from Patterson's usual mystery works.
However, as I progressed through this book, I started to really enjoy it. Patterson's lending of a sassy demeanor to his main character produces an excellent sense of adventure (not to mention that the kid's powers of creation are pretty darn cool).
While the story progresses nicely, Patterson leaves some very loose ends. The Prayer - the beastly thing that murders Daniel's parents in the opening chapter - isn't seen again through the rest of the book (the great majority of the story revolves around Daniel's hunt of alien #6, Seth). This may mean Patterson intends to continue this story elsewhere, but it didn't seem terribly clear.
Overall, Patterson's writing style (including his trademark 1-2 page chapters) and his craft of an intriguing story make this an excellent read.