Will give it a spin a little later. I see it's a free download, and was wondering what the IAP is for? Is it a full game unlock thing, or for extra power-ups kind of thing? Or something else?
@Jake7905 the in-apps are based on Diamonds - the currency used in the game. You can purchase then some in-game features like bonus Oxygen for constructing towers, additional hero or Golem unit and so on. The shops open up after finishing the 4th level.
