I would say, in this case, the downloads are almost 100 percent driven by the feature. I did contact Pocket Gamer and Touch Arcade, both of which provided some coverage before and around the release. I wouldn't say they were press kits, but they weren't informal either. Just a quick email and some screens laying out why the game may be worth their time.
That said, I wouldn't expand my scope beyond those two sites. As popular as those sites are, they don't really move the needle nearly as much as Apple's confidence will. But, trying to reach out to them can't hurt and is better than doing nothing. Just don't go nuts, emailing every site in the world.
EDIT: Actually, thinking back, I did even less than that. I added some press to the TF build and asked them to give it a whirl. TA wrote about it and PG picked up on it without me even contacting them. Around release time, I followed up and got some additional coverage.