This has been my favorite variety sudoku for over a decade. New games of each type offered daily on a set level. For example on Tuesday, you can play a moderate X, tough traditional, tough jigsaw, diabolical killer and moderate Kakuro. Easy games and even an Extreme level are offered on other days. Possibles can be set or cleared, if you want help or to solve the puzzle quicker. I do like another app :) sudoku+ that offers you hints for learning techniques of traditional sudoku while you play. I can then practice with more variety, the games I really enjoy such as X and jigsaw. Also there is no advertising, only the small fee for the app. Really great app, and right now no bugs as far as I can tell. ( I never submit my results so can’t comment on that).