The app is fine, however 2 things I would like to comment:
1. In one moment the coaching stops with offer to become paid. That's fine if I can see it in the beginning of the coach process and not in the middle of it.
2. I am new player. In normal game I would like to test something, then to go back in specific position. Dr. Wolf tells me I have reached his limitations and I can undo only one move. 
Nope, Mr. Wolf, you reached my limitations and got uninstalled.
However he is not guilty. The ppl behind the app set this unacceptable behavior.