The game doesn't seem to involve so much coding. Actually, it's not about the game, it's about how it got around 1 million download.
If you want to show us a 14 kid coding, then get it to do some coding stuff. Example, solve a math. equation or write an algorithm or hack Windows kernel... If you show us 800K downloads, it's just the app success that happens either by good planing and marketing or a sheer luck.
Why would he bother writing his own physics engine if there are free and easy solutions already? People who invent their bicycles don't end up shipping stuff in two weeks with no prior programming experience.
There are layers of complexity that you simply can't avoid. Add that even the simplest physics algorithms are non-trivial.
Many of us were programming before we hit the grand double digits, however in ways modern development is more difficult in some ways because you're building on layers and layers of existing code (Motorola assembly was easy compared to developing for the iphone or Android), which is where experience comes into play.
Nonetheless, the way this story was delivered, the fact that this kid has purportedly made 10 apps...I dunno it seems like a really clumsy marketing tactic.