Rolling thing pushes non-rolling things (first 8 levels)

It's a work in progress, puzzle platformer type game (also the first game I've ever made).
http://www.stencyl.com/game/play/3422

There's a lot I want to edit before I will consider this finished.  I would be interested to see what people think, though, as I'm working on it.  There's a list of things I'm going to change/add in the description.