Yea, this game is a spinoff, for sure. Gives fans the chance to play at the overpowered Ninja class seen in MGS, MGS2, and MGS4.
And this game was developed by Platinum Games, the studio that made Bayonetta. Kojima admitted himself that if he had taken the helm, the game would have turned out much more differently.
IMO Kojima specializes in making games that play like Hide-n-Seek. This game is more like Tag, but you're always It, and lovin' it.