I have been playing this game for over a year on lap top and phone. The free version offers one game per day-can be repeated- for each of the 13 difficulties. It also has 3 lessons if you are just starting with soduku.
The top 5 difficulties (annoying - nightmare) are admittedly over my head and require knowledge of “fishes” “wings” “chains" “locked sets” etc. I can still play those puzzles because i can ask the game for hints (the game even has a learning feature explaining about the above terms). After trying them several times, I still have not developed the abiity to solve these more difficult puzzles on my own.
In general, it offers about 8 games daily of various difficulty for players like me not versed in the “mind bursting” strategies, has easy feature to fill in pencil marks for multiple numbers, offers computer filling all pencil marks, erase button for any cell and check entires feature.
With this game, you can have it in easy mode or do all out and have your soduku nightmare.
To top it all, at the end of each game it shows you the time to complete and even compares to other players without having to do any additional steps. Great for keeping track and pushing for improvement.
Very well done game.