This game basicly goes like this. There are 6 worlds, two of which you have to unlock first. So you start out with 4 worlds, a grassy world, a lava world, a water world, and the icy world. There's no order on how you go to the worlds so you pick which world you go to. Each world has 4 levels level 1 is a normal stage level 2 is a semi boss stage level 3 is like level 1 but it's bigger and more complex and level 4 is the boss of the world. Once you beat the boss you beat the world. Beat all 4 of em to unlock the 5th world the Fortress. Once you get all the gold cards you get a new world I like to call the rainbow world;).