This is a fairytale that follows all the traditional requirements of a fairytale. The two main characters are orphaned kids; one of which (Liesl) is an heiress with an evil stepmother who killed her father for his money. The mix-ups of the boxes allows for an easy plot and the adults are all evil (except for the dead father and the one large hearted, yet dumb guard) and plot to capture and kill the kids. The whole thing was trite and predictable and simplistic. The characters all bump into each other throughout (including the lady on the train who has nothing better to do than to follow two random kids to the middle of nowhere on a three day journey across country AND the one-eyed servant boy who tells not one, but both groups of adults where to find the runaways), making the world a tiny and very unpopulated place. In the end, the all powerful magic brings things back to life that THE VERY SAME ALCHEMIST KILLED BY REMOVING THE SUN...so you know basically he undoes his own harm.
That said, it is a kid's book and was well written and entertaining throughout. Specifically, there were two passages that I found especially moving and I thought that Oliver has great tone and insight: "People need other people to feel things for them...It gets lonely to feel things all by yourself." and "This was the other problem with living ones: They were separate, always separate. They could not know how to be anyone other than themselves, and even that they did not know how to be sometimes."
I will read some of her adult stuff; I'm hoping that the story is less transparent.