There should be minigames you can play that don't depend on energy. The way the game is structured now means you can't binge play it, you just have to wait and come back later, which isn't something I like. I definitely think there should be a way to earn energy through minigames of some kind, rather than either waiting or spending diamonds. Overall it's a decent game with a good plot, but there needs to be a way to effectively 'earn' energy, and ways to play the game that don't rely on energy.