Glad someone answered. I was trying to make another super class for my levels (subWorlds), since they all share stuff like background, but i faced some issue since they are all children of that class. I didn't know how to call them, so i make it simple, they are all subclasses of World. guess will try now to see how it works.

How does it know its going to start from level1 ?? I mean where is the code that tell the world to start the game from the first level ??? Please let me know :) thanks