Make the candidates keyboard bigger! – Big Bad Sudoku Book Review

People who play sudoku use the candidates much more than the actual numbers. If anything, the candidates keyboard should be the bigger one. At the very least, make it the same size as the numbers keyboard and separate it from the strange little function boxes on the bottom. Also, make the puzzles harder. None of your puzzles requires anything more than an x-wing to solve. A good point is that you have separate keyboards for numbers and candidates, so you don't make mistakes with a silly toggle.
Review by Whydontadcomaniesadvertise on Big Bad Sudoku Book.