The artbook also shows lots of concept art and details that not only describe what you see in the game, but a lot of it is stuff that should have been in it but didn't make it.
Go to YouTube. Search Alice Madness Returns Beta Trailer. It's full of old stuff and development things that were planned but never made it into the game, like a swimming level, new cutscenes, new weapons, actual gameplay in the London stages and a rather bloody Victorian scene...
At least two levels were scrapped during development, one in a world based on M. C. Escher's work, and the other on the moon.
One page of the artbook depicts scrapped ideas for being able to smash through barriers while 'dashing' in a run or swim. Directly underneath is a scrapped dress design featuring streams of horse hair and a spiralling horn on her forehead, so clearly someone at the studio was thinking of Robot Unicorn Alice!
An example that also counts as a Take That: Reportedly EA was giving American McGee pressure to ramp up the levels of sex, gore, and general Darker and Edgier Content (to the point McGee explicitly described what EA was going towards as "Dante's Inferno + Alice") in the hopes that the game would get an "M" rating close to the dreaded "A" rating. He gave them Shock Content, all right—the "M-Snail", a deliberately Not Safe for Work monstrosity note consisting of a snail with, well, a penis as its foot/body and breasts for eyes with a friendly reassurance that he'd make sure it made it in the game. Needless to say, EA backed down and quickly, otherwise....
The Cameo: It's possible to find Razputin Aquato's skeleton, complete with battered aviator's helmet, in the Queen's Castle, apparently having drawn a memory back out into the open. Apparently Alice's mind is just that rough.