The Tower Experiment from Animoca Brands blends together "Free-to-Play" and "Play-to-Earn" via the tokenization of a game ecosystem. You can earn tokens by playing on the one side and tokens can also be used to buy NFTs for the game. These are collectibles but also actual cards that will be available to use in-game. I currently play Crazy Defense Heroes on mobile and am loving it, I am looking forward to the new PC game (which is the one that will include NFTs). The whole logic behind the tokenomics and use-case of the token is super interesting for the evolution of gamification through crypto.