Please write any bugs or feedback in comments below. Enjoy the game :)

Isn't it an unfair labeling to sell an expert level killer Sudoku with not a single number in it as easy?

Does anybody know what the two buttons in the bottom left corner do?

My progress on the hard puzzles was deleted after the last update. I now have to do approx. 10 puzzles again (those that I didn't do in order)

This behaviour exists in all 3 games, but Shift+Number only works for Left Shift+Number; Right Shift or Numpad doesn't work, which makes this hotkey incredibly awkward to use. It's even weirdly if you consider that Numpad can fill in regular numbers as usual....