For what it's worth, I have released about 50 apps into the App Store and observed how difficult it is to get organic downloads every time. But, 1 of my 50 apps

For what it's worth, I have released about 50 apps into the App Store and observed how difficult it is to get organic downloads every time. But, 1 of my 50 apps (Bloody Knuckles) for whatever reason absolutely blew up - it got 10K downloads the first day and rose to #2 overall in about 4 days with absolutely no promotion of any kind. Based on my experience, I definitely know that it's possible to have a right place/right time/right game/right app name/icon etc. experience like that and I don't think Flappy Bird's creator did anything to hack the system. Just my $0.02.