I understand this is a demo, but you should have done more. First of all, you may have been testing out whether or not people are interested in this genre. Of course, you didn't need much. But why a demo? If you wanted, you should have added more to it, and a lot more in the complete game. Also, I'm not entirely sure if you are allowed to post incomplete games on Newgrounds, so maybe test it out on friends or something. However, at first I was worried you might have gotten into trouble, because this was an iPad simulation and there were no copyright licenses posted in credits, or if there were any. Luckily, you were reasonable and slightly altered the names that are trademarks owned by Apple.
In conclusion, I like the idea, but people might be playing around on it for about 15 minutes at max if your full version only contains the previewed apps. Add some more, maybe a way to gain currency via a international trading network or something. That way you will be able to buy apps from the My Store, and maybe for the apps make parodies of real successful games -eg. Angry Birds, of course they're angry, they have no wings!- or whatever. Just as long as they are worth it and grab the attention of your aimed audience longer.
I feel as though I might have given you a score too high, but I see what you're doing, and it's pretty original seeing that there aren't many iPhone simulations (not that this is an iPhone, but the apps and everything is very similar), so best of luck to you.