Sudoku "insane" grids

Question

I bought that game a few eeks ago. Like it, well done. But I am disappointed with the apparently limited number of different grids available. In particular, the "insane" level seems to contain only two different grids. Is this true?
I tried to contact Apple Switzerland, but they sent me to a wrong place: iTunes services.
CP

Answer 1

I built a generic sudoku solver which not only validates, but suggests moves /solves an n x m (dimensions can be different and arbitrary) board by using an int[m][n] array for entered value and a Set<Integer>[m][n] for the possibilities. I added a method called runRules() and created rules off of the following two abstract classes.
package tjacobs.games.sudoku;
Remove possible values on cell row,col using the entered values in the board
public abstract class AbstractCellRule {
     public abstract void runCellRule(SudokuBoard sudoku, int[][] board, int row, int col);
package tjacobs.games.sudoku;
import java.awt.Rectangle;
For rules dealing with a range (row, column, box) in general, not focused on 1 particular cell
public abstract class AbstractRangeRule {
     public abstract void runRangeRule(SudokuBoard sudoku, int[][] board, Rectangle bounds);
}