Since this is the second comment about getting stuck on the first level, I figure I should give a bit of context, as well as a direct hint for anybody who's stuck.
The first level of this game uses a puzzle design that can be found in other puzzle games. However, using only the game mechanics that are immediately obvious, the puzzle is unsolvable. The purpose of this level is to help introduce the main new mechanic for this game. If you get to the last step of the puzzle you can do without the new mechanic, the game gives what I think is a fairly direct hint at what you need to do if you haven't already figured out that mechanic.
If you are still struggling with the level, here's a hint. EDIT: I moved the hint to the game's main page in the description, as I figured out how to make a pseudo spoiler tag there.