You may have just gotten clickbaited.

Let me elaborate. Cradle's "world acquisition" system draws in any number of worlds and their inhabitants from wherever. This method of transportation does not seem to be the result of physical actions; rather, it's almost as if some form of teleportation were used. Maybe that's not the case, but it leads me to this:

What if we could reverse this transportation method to travel to other worlds? This would involve a lot of "surface" levels on the faces of other planets, with a "portal" or "spaceship" type thing at the level's end instead of an elevator. These end-of-level entities could transport you back to Cradle instantaneously.

Alternatively, there could be a path up to another area players could take to explore more of the world.