World of Goo is a fun puzzle game. It's far from perfect, but it is definitely worth it. You try to get to certain areas by using a chain of goo. You can use these goo balls you collect in various ways as this game does not stop you from being creative and finding outside the box ideas. This is actually a physics game as you will need to do a lot of counter balancing. There are several "species" of goo balls which wil be very different from each other. This game gets very challenging very fast and your little kids may be a little frustrated at times trying to beat the game at certain levels. The game has an alternate mode called the Goo Corperation in which you try to build a gigantic goo tower. I couldn't care less about this mode, but hey at least its something different. This game/app is very good. It's one of the better apps I've played for the iPad and you hould buy this app.