I played this all the way through on my iPhone, then again from scratch on my iPad, and then on my '13 Nexus 7, and now just finished yet another playthrough on my Note 2. It is baffling to me that this game didn't get GOTY, it is pretty much perfect design and execution. If there is *anyone* out there that didn't get a chance to play this... Sheesh, remedy that situation post haste.
The Android release has been done in a classic 'shareware' release, where you grab the game for free but the upgrades are locked above a certain point at which you pay for the game to advance.
Oh man, do we ever need a sequel for this one.