Ten years ago, I had a Palm Pilot. The Palm OS was a winner. It had a simple programming language (C-based, I think), a form application framework and a database. That's it. None or very few apps came with any graphics. Still, you could download tens of thousands of applications back then. Fart logs, excercise diarys, vinyl databases and so on.
Ten years later there's three platforms covering that same market, iOS, Android and Windows Mobile. Nokia is eager to get back into the lead, and you still have Java for all of those old fashion mobile phones.
So, if you write a sucessful fart log application on one of these platforms, odds are that you would like to expand onto another platform and you would have to fork your code in order to do so.
My prediction is that the web will be the leading platform in a few years. Safari is big on iOS, Opera is taking the lead on other smart phones. Firefox is still in beta (alpha?) with their Fennec browser. Internet Explorer, I haven't tried on the new WinMo 7, but chances are that there will be a browser war on mobile units. And that's going to benefit all of us.
EDIT: The game should work on IE 8, Firefox 3, Chrome 7, iPhone, Android and possibly WinMo 6.5 with Opera mini