love this game, finally a quality app I didn't regret paying for. sometimes the game controls become unresponsive, not the touch input, but the popup menu items.
if I complete an object and then return to it none of the game options function, such as "restart" or "exit", and the "X" in the upper right corner doesn't quit the game. the only way to quit the game at this point is to minimize it with the keyboard and tap the "x"