I have played similar puzzle games before so I know these questions are not as easy as you think, or they seem impossible to solve but actually not. The overall giving me a feeling of relaxing and silly, I can use normal way of thinking to these levels, they are laughing at me...
When I stuck for too long, I can watch a short ad to get the key, key can give me hints so I know how this puzzle stupid. And yes, there are ads but not too frequent. Still recommend playing even if you played a similar game.