Gameplay Walkthrough:

1. Opening the Game:
- Launch the Sudoku Offline app on your mobile device.
- The main menu will appear, displaying the available difficulty levels: easy, medium, hard, and expert.

2. Choosing a Difficulty Level:
- Select the desired difficulty level by tapping on the corresponding button.
- Start with the easy level if you're a beginner or choose a higher difficulty level to challenge yourself.

3. Starting a Puzzle:
- After selecting the difficulty level, a Sudoku grid will appear on the screen.
- Each grid consists of 9 rows, 9 columns, and 9 3x3 sub-grids.
- Some cells already contain numbers, while others are blank.

4. Filling in the Numbers:
- To solve the puzzle, tap on an empty cell to highlight it.
- Select a number from the number pad at the bottom of the screen and tap on the empty cell to fill it.
- As you fill in the numbers, the game automatically checks for errors.
- If you make a mistake, the incorrect entry will be highlighted in red, allowing you to correct it.

5. Using the Notes Feature:
- For more challenging puzzles, you can use the notes feature to mark possible numbers for a specific cell.
- Tap on an empty cell and then tap on the pencil icon on the top-right corner of the screen.
- A mini number pad will appear, allowing you to select multiple numbers for the cell.
- These numbers appear smaller and do not count as actual entries.
- Use this feature to eliminate possible numbers and identify the correct ones.

6. Hints:
- If you're stuck or need a bit of guidance, you can use hints to get closer to the solution.
- Tap on the light bulb icon at the bottom-right corner of the screen.
- A hint will be provided, revealing the correct number for one of the empty cells.
- Use hints sparingly, as they are limited and can only be replenished with time.

7. Progress Tracking:
- To keep track of your progress, tap on the graph icon at the top-right corner of the screen.
- The statistics screen will appear, displaying your best solving times for each difficulty level.
- Challenge yourself to improve your times and aim for perfection.

8. Solving the Puzzle:
- Continue filling in the empty cells with the correct numbers based on the Sudoku rules.
- The goal is to fill each row, column, and 3x3 sub-grid with the numbers 1-9 without any repeats.
- Be patient, observant, and strategic in your approach to solving the puzzle.
- Each puzzle has a unique solution, and with dedication, you can conquer even the most difficult levels.

9. Completing a Puzzle:
- Once you've filled in all the cells with the correct numbers, the puzzle will be solved.
- A congratulatory message will appear, and you can proceed to the next puzzle or return to the main menu to choose a new difficulty level.

Conclusion:
Sudoku Offline provides a challenging and enjoyable offline gaming experience for Sudoku enthusiasts. With its user-friendly interface, multiple difficulty levels, auto-save feature, and helpful tools like notes and hints, it offers a satisfying puzzle-solving experience for players of all skill levels. Whether you're a beginner or an experienced Sudoku solver, this game guarantees countless hours of brain-teasing entertainment. Download Sudoku Offline today and put your puzzle-solving skills to the test!