While I cannot read Japanese myself, Andriasang, the website that first broke the story, claims that "in Hiku-osu, you play as the powerful Maro who's out to help people. Maro's town has been covered in a mysterious block-like toy called Hiku-osu." The story at Andriasang also claims that the game will include 250 stages, will be released on October 5, and will cost 700 yen.
Nintendo does have an official site up for the title, but besides noting that there are a few extra videos located on the page that one can view, there isn't much else to understand if you cannot read Japanese. Sorry! You can still look at the adorable pictures, and who doesn't like that.
Screens after the break.