The long version: this is the reveal of something publisher XSEED was cryptically teasing yesterday, with a series of images on Twitter including a Tyrannosaurus Rex, a blade of grass, and a still from Ghost's famous pottery wheel scene. And now you're confused.
It's now clear that the clues refer to the dungeon crawler released in Japan as UnchainBlades Rexx. (get it: "Unchained" Melody plus "blade" of grass plus T. "Rex.") It was a retail game over there, but being in Nintendo Power's "Download" section suggests that XSEED is improving the distribution method along with the name.