Pretty fun, but here's some helpful advice-- some people (often including me-- and a few reviewers below) are morons, and either take a while or are unable to figure out a game on their own. In the first level maybe you should indicate that you're supposed to click on one of the green blocks to place it.
Again, for the benefit of others who'll spend five minutes bashing their mouses in frustration before (while drooling on the keyboard) write something to the effect of "Z0MG DIS IZ T3H LAYMZ0RZ CUZ I'Z A BRAYN-DED M0LUSK!!!111!1one"
CLICK ON THE GREEN BLOCKS, AND PLACE THEM SO THAT THEY BOUNCE THE CHARACTER AROUND
Seriously, idiots not being able to figure out the game is a dumb reason for you to receive unfairly low scores.