I really like this, despite, or perhaps because of its simplicity. The gameplay is unique and real prize in this game is simple sense of discovery you get from figuring out the simple mechanic.
I see this uses the Kongregate High Scores API, but I wish I didn't have to submit my score manually for it to show up. It seems like pretty much every other game automatically submits my score for me.
Great revision of a really fun game! Thanks for putting in high scores. I miss the mechanic where the smaller rocks would travel more slowly than big ones. It'd be cool to see this game incorporate the kind of scale / camera stuff we see in games like Cosmic Crush.