It closes before it starts
I absolutely love your version of “find the difference”. After level three of the 150 levels the puzzle closes before it opens. I turned off the iPad for a few minutes and tried again. The problem continued, so I deleted the 150-level app and installed the 100-level app. After level three the same problem occurred. I don’t see where a person should pay for the app after level three, but it doesn’t work after level three.