Explanations

Check

Checks if there are any direct violations of the Sudoku rules. A Sudoku that doesn't contain such a violation may still be wrong if it is not filled entirely.

Validate

Checks if all entered numbers are correct.

Hint

Enters the correct number into one randomly chosen cell.

Solve

Solves the current Sudoku.

Hiscores are ordered primarly by the sum of the hint, check and validate, and secondary by the time (penalized).