Soooooo many pop ups every time you open the game. Very annoying. You need gems to to progress (upgrades and new islands) and takes a long while to get them without spending money. The game allows you to earn gems by downloading or gaining achievements from other games. But from my experience, they are not always applied to your account and the creators of the game do not honour the gem offer. It is a time filler but I would not invest money into this game. Not suitable for children.