Great idea! A mini-game is ideal for an objective between 18 years and over. Because there are certain warnings about the use of Bitcoin that are clearly understandable.
It can be fun if users have challenges and missions where they can earn rewards and points. Also, with the points earned they can become satoshi, it would be an advantage.
It would be hard to associate game to bitcoin or cryptocurrency specially when you are playing an online game and the reward is a cryptocurrency which is satoshi or any coin i think the developer of the game will be having a hard time f that would be the concept of the game playing the game winning the game and earn free satoshi a after the game maybe that would be a hard part for the developer.
I think the main concept will be just the game will be having a connection to cryptocurrency and bitcoin and which they will how to promote or introduce bitcoin is.