Note: we describe here only the menu items that are game specific and skip KDE standard menu items.
Select the game difficulty. Harder games have more balls and bigger black box than easier games. You can also play with a custom difficulty level that you can set up in the setting dialog of KBlackBox.
Note: games with 4 balls or less can always be solved with certainty! That is not the case for games with 5 balls or more.
In this dialog, you can customize the number of balls, columns and rows of the black box in the custom difficulty level.