Fun and Easy
Well, first off the instructions are wrong. You can see two layers at once; the current layer, and the (outline of) the one above you.
Good, fun, a bit complex... would benefit from a tutorial that showed the map from a 3-dimensional (isometric, perhaps?) perspective for the first level or two, then show the flattened view for the same level(s), then on to the real challenges.
Beat all ten levels. Pity, those folk who gave up at the "The End" fake-out screen.