I really like this. I've thoguht what a puzzle game would look like without challenge, and this is a great illustration of that idea. Gradually cleaning up the sprite gives the same satisfaction as watching a drive defragmenter slowly rearranging files. I wonder if starting from no-brainer and gradually adding mental effort can make an effective puzzle.
My one criticism is that some of the sprites don't stand out well against the gray background; maybe make it a bit lighter?