Given you poured your soul in to it, you get a ten
So what's right with it?
Well a lot of things. If it's not mentioned here it worked so please don't think it didn't :)
I loved the pop out introductory you brought from page (book) to world (popup drawings), led (sketch) to life (green, lush, vibrant). Awesome transition. The fly throughs were well set up and perfectly timed.
Your changeover of skethc, and cartoon, to real life, and back aagain worked out well.
Awesome conceptual piece.
So what's wrong with it?
You need a loading bar. Plain and simple. Telling people the size of the movie at the initial load sequence is great and all but if I can't visually see the progress I don't give a damn. A progress bar makes all the difference in the world to judge what you have time to do with when it'll be ready.
The lens flare was abusive. It should be there as much as it was. For a scene switch it would've worked except it was introduced way too early and annoys the viewer as they try to see the work being progressed through. Lens flares should never hit until there's a direct light source to cast from.
The AE mask for tree switching was well done but it looked like you switched to a still photograph of real trees in the woods. For something that's animation based, I wouldn't expect still frame photos in it. It could have been the blur effect as well that contributed to this feeling. Essentially this scene could've been taken out and the following scene moved over and slowed down on load a little to fill the gap.
Overall though great piece. Really impressive. :)