Originally Posted by FayMay
The app checks if you have played it already before this update. If so it unlocks all levels for free. That's why the Dev says you should e-mail receipt to them in case you have deleted app or reset iPad, in which case there is no way for the app to know if you have played it previously. It's a common problem on iOS. Apple should do something about this. Great games like Drei get bad feedback because of this now, not so fair.
I'm betting most of the bad reviews are from people who were lucky enough to download them game for free, the full version, then updated to find a premium version has replaced it.
It's not really unethical for non payers, but it is Indian giving.