The big distorting effect here was that it was available for a long time on iOS before other platforms -- if you wanted the game, initially you had no choice other than iOS. And despite it being significantly more enjoyable on a touch screen, it was ported to Android last out of all the platforms supported.

Anyone know of a major game that had simultaneous releases on both Android and iOS at the same price?

e: Oh, another factor: it was available through the Humble Bundle on Android before it was in the Play store.

I guess I should also mention that it's a pretty fun game. :)