Perfectly 18+...

It's a standard tile-matching puzzle using mahjong tiles, but the success reward videos are quite explicit, so I can only recommend it to those 18 and older. Gameplay-wise, ads pop up during the puzzle attempts, making it quite stressful. Also, the game resets with a considerable probability, which is another factor contributing to the stress. However, the high gem conversion rate might be a plus? I'll say it again: the content is explicit, so those under 18 should not install it.