The facets in the bubbles are really quite amazing. I'm very impressed by your photography, in case you cannot tell.
What facsinates me is that it appears that inside each bubble, there is another bubble, and then another, such does the light play. It almost looks like there are many worlds inside one, and that it all depends on another. The bubbles in front are very clear and precise, and stand out very nicely from the ones in the back...Perhaps that's the really defining part of the picture.
This resembles something like a cutscene in my dreams. I know, I have weird dreams. I think the bubbles in the background add a nice effect to the ones in the foreground. As *alyn said, good use of focus.
What a cute title for this. ^_^ It's a nice touch to make that one bubble that's focused in the center with a cute little trail below it. All the bubbles surrounding it in their different variations of blur really frame the one bubble nicely.