Wouldn't it be easier to start in your level picker world? It can be used not only to keep track of progress through the levels, but also as a title screen, where starting the scenario (that is, when the user clicks on the "Run" button) prompts the tile showing (by using the "started" method WITH some condition that it is indeed the initial starting). I have a demo of a support class which behaves in this manner -- Super Level Support Class. Here is a thread of a discussion with a brief explanation of how to transfer to game worlds and return to the selection world. Well, the mechanism is the same, however, the starting point is just shifted down a world.