Kaze and the Wild Masks.

no i didnt.
Maybe you downloaded the demo?
there was an free weekend?
or you have family sharing and the person is using their account?

have you tried just closing down and restarting steam? i've noticed in the past sometimes the client just needs a kick in the ass to find new games if they were recently purchased. if that doesn't do anything you could try going to the game's support page via the library tab. i assume you bought the game from steam since it just came out today and i don't see it listed on any other stores. i would imagine if one bought a game from them, and their library isn't recognizing it, they could help you out. at the very least give you a refund.

I'm sure it was beta key from here, full version just released.