Sudoku HD!

The app closes unexpectedly and I lose my progress. In order to play, I have to constantly return to the main menu, then resume my game to save my progress. I have purchased several sets of puzzles. I am using iOS 15.8 on iPad Air 2, which is the latest iOS for the device. Even after saving constantly, sometimes puzzles crash constantly and will not allow me to complete them.

Optime Software has gone the distance in producing Sudoku HD. I've played 23 others on iPad & PC but deleted all but this one. Why? It is simple: # notation that allows multi-input, auto erase when correct # is placed, color alternative for wrong answers, thousand plus puzzles and the most categories imaginable. All that on top of beautiful graphics even oh my old iPad, no plus either. If you've not tried this game, and you love Sudoko as much as I do, don't wait any longer, just trust me and get it. There will be no buyer's remorse whatsoever. I promise.

Overall, I think this is a very nice edition of a Sudoku puzzle game. I would like to see 2 specific things added - one, something to show you when all of the number has been used in all nine squares and I would like to see them remove the penalty for mistakes. Most of mine are silly and I don't think it should matter. Or offer an option that elects to highlight mistakes with a penalty or NOT show a mistake and NO penalty..