In 1580 A.D. you are taking down the undefeated Tower of RööK no matter the costs!
One in-app purchase of a Mega Set of Cannonballs gives you unlimited firepower through the end of the current game. Returning to the main menu updates your leaderboard score in Game Center.
If you have experienced severe motion sickness, or seasickness, in the past then you are advised to avoid playing RööK. Seriously.