Fine, but lacks full screen mode.
Also explanation of what tetris, puyo, and combined modes mean.
Other than that, cool game, though nothing really relating to folklore theme or to make the player stick to it.
Adding a campaign could be a nice thing.
Like, a story had been told that once cubes would conquer all the world, and nothing would stop them. You need to build a wall to prevent cubes from conquering the world. And more and more.
ALSO, being able to rotate in both sides would be a benefit. As well as change the level size, because the default one is quite small.