Not to sound whiney, but I really did find this a bit too difficult. I guess it is a fairly original idea when you think about it. What I didn't like was how the blocks could only go from down to up. It seemed less than "Tetris". I know I want originality, but that made it less enjoyable. It still isn't hard to figure out, at least.
There could also be some more detail. It was interesting to have different levels of difficulty. I really need to start from the easiest. I'm glad the Enter key can speed everything up. While hard for me, it did go a bit slowly.