That was based on the Japanese Marketplace saying they are pulling that game. There was no mention of the US store, but we are being cautious.
Delisted games can usually be re-downloaded if already purchased through your purchase history, but you would not be able to find them through the external channels.
Since it is a single player game - there isn't any concern over achievements being unobtainable and the game should function normally. You just wouldn't be able to buy it moving forward.