First-Person Central and Peripheral Narrator
Is it weird to say "first person" when our narrator is a dog? Maybe "first dog" would make more sense?
Anyway, this story is told simultaneously with a first person central narrator and a first person peripheral narrator. It sounds a little confusing, but believe us, it works.
Enzo is reporting his life story and the life story of his family. He uses first-person central narration when talking about his own feelings and reactions to things, but then he also uses the role of peripheral narrator when he's talking about his family. Basically, Enzo may be the center of his own story, but he's a peripheral character in the story of the humans, which he's also telling.
Enzo's peripheral narration can leave us just as frustrated as Enzo is: he can't ask what Denny was thinking when he took Annika home, for example, nor can he ask why Eve disliked doctors so much, even though we would love to know the answers to these questions.
This mix of narration and retelling ends up creating some hilarious, witty, or poignant moments, like when Enzo tells us that he knows that Denny could keep going with the custody battle: "How did Denny sustain himself for the duration of this ordeal? He had a secret. His daughter was better and quicker and smarter than he was. And while the Evil Twins may have restricted his ability to see her, he received all the energy he needed to maintain his focus" (42.24).
Enzo's observations make for some great commentary, like when he calls Maxwell and Trish the "Evil Twins" and declares that Denny should roast Annika on a spit.