Slow and buggy ... Not as good as free version
I paid the fee to buy the upgraded version of chess without the ads since the free version was ok.
Unfortunately, the paid version plays slower and has several bugs; at times the computer playing side will "cheat" e.g. move a pawn horizontally (like a rook) or advance (4) spaces forward at a time, at which point the game is over because it will keep trying to do the same crazy move again even if you hit "undo".
It gets worse, towards the endgame, pieces will freeze movement or even disappear for no reason. Last, when it is advancing a pawn towards being promoted, it will give it the move powers of the queen before it even reaches the final row ... This can't be undone, ending the game.
If you try to speed the game up, the computer just plays poorly, making dumb moves. Not a completely horrible app, but not more than 1 star