The blocks definitely do not move two squares at a time, however the key repeat rate is quite high, I will consider adjusting it in a future versions as others have also struggled with this. As for the blocks falling through, I am afraid you have not understood the game mechanics. Blocks do not land on the silhouette, they land on the ground. if you wish to build on parts of the picture which overhang, you must balance your block on a neighbouring shape and build across-ways.