It's out already on the European eShop
Nintendo has a new trailer up for Summer Carnival '92: Recca, an obscure shoot-'em-up that's already live in the European 3DS eShop, and set to release worldwide at a later date. The game has a unique history, in that it was developed in 1992 to push the NES to the best of its ability (mostly through an extremely large sprite count without framerate drops).
But it was also extremely rare -- very few copies circulated in Japan. Shmup fans generally consider this not only a rare gem, but a good one at that, so check out the video if you want to get the gist of Recca, and keep your eyes open on your local eShop.