From Vorwerk & Stengel:
The game board is divided into two parts: the kind of blocks you need are displayed below the black line. Above that line that is the actual game board. When clicking on a block, the number of blocks of the same color in that line will be calculated. If you need exactly that number of blocks in this color, these blocks will disappear and the blocks above them will fall down.
Version 1.2.1 features unspecified improvements and bug fixes.