Don't get me wrong. Super Scribblenauts is a good and fun game, and is definitely worth the rent. But, thats only if you have nothing else to rent.
It seems like they spent a lot of time and hard work on this game-- but actually, they really didn't. I swear I spent more time on the title screen than I did in the actual game, and that really made me realize the amount of restrictions: I wanted to make a cave full of werewolves, and there would be werewolf families including the mother, the husband, and the son/daughter. But, even if I put in "female" besides "werewolf", she still looked exactly the same as the husband and son/daughter. I also wanted to dress up, or even be, as a werewolf, but of course there was no "werewolf costume", and I had to put on stuff that looked, barely, like one. After that, I'd wanted to make a city with a bunch of people and buildings, but the stupid cap got in my way. They could have increased the cap for the title screen-- maybe even made it infinite; its not like you're cheating a puzzle or something, and even added more items and characters. There wasn't many puzzles in Super Scribblenauts, nor was there any way to get more unless you made your own or got one from a friend of yours. Actually, I don't even know exactly if the friend thing works, because like many gamers in the world, I have none. Go ahead, laugh, but Karma will get you back.
Besides those "little" things, I had a lot of fun playing Super Scribblenauts. I didn't play it for longer than a few hours, but I still had fun in those hours. I liked the uniqueness of the few puzzles they have to offer, and they always kept me wanting more when they were over in a short time. The graphics are nice for a DS game, and they are really quite "cute". Sometimes I wish we had a different sprite for Maxwell, though, so that I can dress him up like James Bond or the Matrix.
All in all, like I said before; its worth the rent, but only if you have nothing better to rent. Happy Gaming!