It is totally free with no ads. It has the power of allowing you color numbers so you can test solutions as you like. It can do Sudoku and Futoshiki. You can set up any outside source of Sudoku and Futoshiki. It has Sudoku/Futoshiki checks which you can choose to include or not include for most colors of numbers (only givens which are black are always checked). Please tell me what you think it.
https://cloa513.itch.io/su