There's so much to love about the Lost Code, but I'll try to keep it brief. Owen is an every-boy, not someone that anyone would think is special. Yet as he comes into his own in this dystopian setting you start to see that he really might be the one who can save his world. Add a cute girl and a creepy nemesis and the story is good to go.
I cannot say enough about Emerson's portrayal of teen dynamics. It was so spot on it gave me goosebumps. Very few adults can write about the shifting and exclusive world that they live in. I would read it just for that. Owen's relationship with Lily is the perfect example of that. While most YA has only a few core characters at most, The Lost Code is full of well fleshed out characters that act with their own motivations. Either Emerson did his footwork with each and every character or he has an innate ability to see every character, no matter how minor, in 3D.
There were negative aspects as well. The first part of the book was really slow, and it didn't speed up too much. Plus the mythology was really weak. It was six of one half dozen of another when it came to the whole magic/technology thing. I felt like it was supposed to mesh really well between the two but it just felt flimsy.
All in all this was a great learning tool for me as a hopeful writer.