Here are my thoughts after having completed 200 levels. Gameplay is fun. Simple mind numbing puzzle. However the ads feel somewhat predatory, targeting both the super young and the elderly. Half the ads are people getting basic math wrong, and the other half has, "what's your brain age?" plastered on the top, likely in an attempt to let Grandma feel good for solving basic puzzles. The x button on the ads is too small and the skip button on some of the ads changes place/icon for some ads.