What factor in Scribblenauts that can be called an "ambitious project"? Simple, the first thing that players have to know is that Scribblenauts are re-introducing a lost type of gameplay--which is emergant gameplay.
Emergent gameplay is a term used commonly in video game development, in which the ways of video game to be played is unexpected, even from the game designer's original intent. Meaning that there are limitless possible ways to play this game, in which the ways to finish a certain level is unlimited, and this is the core gameplay of Scribblenauts.
Scribblenauts was played by controlling our main character, Maxwell, in a platformer-genre game using the bottom screen. On the top right hand corner, you will see a note-like icon. When you touch that icon, a keyboard will appear on the screen waiting for your input. Here's what interesting about Scribblenauts. Everything you typed in, yes, everything, will show up in-game. E3 2009 shows people inputting unusual objects such as stegosaurus, flamethrower, and an AK-47, and even God and Death; with the result of that item appearing.
This is what the core gameplay for Scribblenauts is. One example of the puzzles in Scribblenauts: a cat is stuck on the roof. From this, how many possible ways can you make the cat go down? Use your imagination, and even the most outrageous thing can be emerged to save the cat. For example, you can be a normal person and 1) create a 'ladder', then allowing Maxwell to climb and save the cat. Other way, you can 2)lure the cat by making 'plate' and 'fish' appears. For normal people, this is the easiest possible way.
But Scribblenauts is more than that. Anything is possible here, including 1) creating a lift so that Maxwell can save the cat similar to how he used the ladder; or 2) making God appear and miraculously save the cat; 3) making a 'catapult' to fling our main character to the roof, taking the cat; then creating 'cushions' down the roof so that our character and the cat won't get hurt.
Another case, you are in a desert, and a thirsty man appear infront of you. The only way for you to proceed is to give him water in any way. Being the normal person, you will 1) summon a 'glass of water' then giving it to the man; or something more luxurious, such as 2) giving the man a lemonade instead; or making it more natural, by 3) summoning 'rain' or 4) summoning 'oasis'? But there is more than that if you used your imagination in Scribblenauts. How about 5) making a 'coffee shop' and giving the man 'money'? He will immediately go inside and buy a glass of coffee to quench his thirst.
Last case. Infront of you is a pool containing sharks, and you must go across of it without getting hurt. You can 1) create a 'bridge' to pass through; 2) summoning a 'kraken' to kill all the sharks; or 3) luring the sharks by summoning 'meat'. Anything seems possible in this game, as long as you have the creativity and imagination.