It's a four player mahjongg game where the player is one of the girls and the end hentai image depends on both the winner and the loser. Sounds like a good one, right? Well... the devil's in the details. You have to play an entire 16-round game to get to the end, and even then, you need to win. Given the amount of hentai present compared to the mahjongg, I'd say you need to like mahjongg much more than the adult content.