SudokuNX

SudokuNX has intuitive interface. Before playing a game, select the difficulty level (Simple, Medium, or Hard). On selecting “Play”, a 9 by 9 grid appears with some numbers already filled in. Your aim is to fill the remaining Cells. Also, notice that the 9 by 9 grid is further divided into 9 sets of 3 by 3 grids. Fill the Cells with numbers from 1 to 9. A number should occur only once in a Column or a Row, and also only once in a 3 by 3 Grid. User inputs are shown in Blue while the numbers that are already present in the grid are shown in Black. You can Mark a Cell for tracking purposes. A Cell once marked will appear in Green. You can un-mark it by clicking “Mark Cell” again. You can Reveal a Cell if you are stuck (i.e. see the correct number in the Cell). A cell once revealed with be highlighted in Red background and Green text and cannot be changed, after all it has been revealed to you! You can check your progress by Evaluating a Cell or the entire grid. Misplaced numbers will appear in Red. You can also Save the game and resume it later.