I play this app a lot. I think I have tried most of the games for iOS. I DO like the layout of this game and I like the speed setting for quick entries. However, you have to watch ads to play a game, in the middle of a game, after any pauses to resume a game, between switching game types (even if you haven’t played the previous game)… These aren’t quick ads, they are 60 second tedious ads that you have to click through to remove. But, I liked Sudoku enough I decided I would pay. It is subscription based (not one price) and the fee is per week or year and excessively high considering all of the this app apps available out there. All I can say to the developer is WHY? Why would you price your app out of the competition?
My bottom line advice? You can get the same this app puzzle-solving fun for a lot less somewhere else. There is nothing so special about Sudoku that would make it subscription worthy.