This is...

The game itself is simple with 3 things. However... there are way too many ads. After clearing, you have to watch a short ad (about 30 seconds), and then another longer ad (about 1 minute) to get 3x the gems, which makes the time-to-reward ratio really bad... Around 550 gems is the limit. The rewards are appealing, but this is just too much (> <｡)