I am especially impressed with the backgrounds (which take up a good 80% of the book). So inspired, I wanted to make some digital speed-painting concept art too:

Ballroom/music room of Quent's mansion.

Deck of the Nautilus.

Also, doodle of Professor Layton. My little sister got "Professor Layton and the Diabolical Box" for Christmas and is so kind as to let me borrow it : ).