One of the things that makes this book so readable is the style in which it was written. The prose seems to flow from one thought to another so smoothly that you find yourself following along with the narrative, oblivious to time slipping by in the real world.
So not only is your attention held by the various adventures our characters are facing, but you are sucked into the story because there's nothing jarring you back into reality. The language glides along smoothly, and all of the word choices seem deliberate—so there isn't a sentence you think that Oppel could've phrased better, and your eyes stayed glued to the page.
Finally, the style is very picturesque in the sense that the author does a wonderful job of making sure you always have a clear picture in your head of what is happening and where our characters are. For example, instead of just writing that Matt wanted to go from one end of the ship to another Oppel writes:
I dropped down onto the keel catwalk. The main thoroughfare, it ran the entire length of the ship, from the control car, the officer quarters, and the luxurious passenger decks near the bow all the way back to the cargo bays and crew quarters in the stern. (1.43)
In fact, we're pretty sure that if you wanted to, after reading the book you could draw a detailed diagram of the ship and have it come pretty darn close to the one that was created in Oppel's head.