Ars Technica has their review up:
Scribblenauts was the darling of E3, rounding up a hojillion awards—including a Golden Ars—and impressing everyone who stopped by for a demo. It was a game that showed very well, especially with a developer on hand to point out any number of interesting situations. The premise is simple, although it hides an abyssal depth: you are asked to either reach a star, or to fulfill the requirements to earn one. The tools at your disposal? The world.I'm working on getting my copy still (hopefully before the weekend). Chances are I will hate the game since I'm hyping it up, but that's life.
You can type in or write any word you can think of, and get that item or person to help you in your quest. No dirty words, and no proper nouns, nothing copyrighted—but even without those limitations, you're looking at tens of thousands of items. Type in "pirate" to fight a ninja. Type in "bridge" to cross an expanse, or type in "motorcycle" and "ramp" and jump it. You gain currency by using fewer items, and also by using creative solutions, and you use that currency to unlock new worlds.
There are two types of levels: action levels where you simply have to get to the starite item, using your reflexes as well as your wits; and puzzle, where you are given a one-sentence instruction about what to do. It may say "get rid of the rats," and in that sentence are dozens of possibilities. In fact, you only completely clear out a level by finishing it three times, without using any item more than once. Much harder than it sounds.