Makes me think of atoms and molecules.
Let me explain. The background hum sort of sets a background for the whole scenario. Its liquid, its constantly moving. I forms and creates boundaries according to the quickly moving little specks moving on it. The donkey kong beat you have is the furious movement of the atoms, and the initial push into the mix is the particles coming to life. The beep's give me the notion of a molecule combining with other molecules to form a bigger one. All in all. The piece is by no means basic. But has a musical quality about it that addresses a deeper, more basic thought process or inner room. Its a paintbrush or lens for an area of the brain which is tough to activate, yet with a certain stimulus, allows it to unfold and reveal itself. In short, yet another great piece to sleep to, and another beautiful piece period.