The game has sold out at both Yodobashi Cameras in Shinjuku, Bic Camera in Shinjuku, a Sofmap (dunno where!) and a TSUTAYA (ditto!).
The game went on sale February 5th, and some retailers don't think they'll be getting in another shipment until today or tomorrow. The brisk sales might be the result of low initial shipments not anticipating this type of demand.
The first day sales of the game have sold through 80% of the whole shipment in 1 day itself as reported by famitsu.