That would mean Soul Sacrifice is the Vita game he semi-accidentally announced, and then attempted to unannounce, earlier this year. Inafune is working with developer Marvelous AQL, with composers Yasunori Mitsuda and Wataru Hokoyama providing music.
The game allows players to cast powerful magic spells, but requires a payment ("Sacrifice") for each. You can sacrifice objects, but the most powerful spells require you to give up parts of your character's body – in an example given, you give up an eye to summon a Gorgon. The player has been enslaved by a sorcerer, and captured in a small cell, when a demonic book appears that allows the player to experience past magical battles – which you can do with up to four players.
Head to Famitsu now to see many, many screenshots and pieces of