I agree with others about in app purchases. I have this turned off by default. So the only way to purchase the app is to turn in app purchases back on. So I did and I purchased the app, then I turned it off again. I then went to our second iPad and tried to download the "purchased" app. No luck, it only installs the trial. So it would seem that the in app purchases are meant to get money for each install per device, even if they are linked to the same account.
Puzzles are a let down. It's the same puzzle pieces in the trial. Just a different amount of pieces. I figured they would be literally different puzzles. But in the developers mind a 3 piece snake puzzle is a different puzzle to a 4 piece snake puzzle. All the same shapes. Head, body tail. Or head, body, body, tail. I know it's called snakes but this is lazy.