Sudoku Extreme: Classic Number

This application is a Sudoku puzzle game that has only one solution. The puzzle comes with some cells already filled in, and the player's task is to fill in the remaining empty cells with numbers 1-9. The goal is to ensure that each row, column, and 3x3 block contains only one instance of each number.

The app has no ads or subscriptions and offers 6 levels of difficulty: beginner, easy, medium, hard, unfair, and extreme. It also has a variety of customizable themes and settings to make the app personalized for each user. The app even has light and dark themes for those who prefer a specific color scheme.

If the player gets stuck, they can use the notes and hint features to help them out. However, using hints will not earn the player any points. The app also has a haptic feature that provides a positive vibration when the player enters a correct number and a negative vibration for a wrong answer. This feature can be disabled in the settings.

If the player makes a mistake, they can use the undo, delete, and redo buttons. However, each mistake will result in a deduction of points from the overall score. The game can also be restarted by long-pressing the undo button.

After completing a game, the player will receive their overall stats, including total time spent, best time, average time, overall score, hints used, and mistakes made. The app also has a graph that shows the player's progress over time. As the player completes more difficult levels, they will earn more points. Each higher level gives twice the number of points as the previous level.

The game can be paused, and the player can resume their previous game when they come back. The app also has an auto-fill feature for notes, but the developers encourage players to disable this setting and fill in notes manually to keep their brain active. Manually filling in notes also earns the player extra points.

The app has a quick fill feature that allows the player to tap and hold a number and then tap the cells they want to fill with that number. The numbers also show how many instances of that number are left to be filled in the puzzle. When a number has been used correctly nine times, it will hide itself. This setting can also be disabled.

The app also has a feature where the player can swipe up or down to quickly enter note numbers without having to enter edit or note mode. This feature can be enabled in the settings.

Players can also export their scores from the app, which can be used in Excel. The app offers advanced levels, theme customization, and settings customization as a one-time in-app purchase. There are no subscriptions or ads in the app.

The developer of this app offers a beautiful and ad-free experience for their users. They also do not use any trackers or analytics. If players enjoy the puzzles, they can leave a positive rating on the app store or support future updates by purchasing the one-time in-app purchase. The developer also welcomes feedback and feature requests via email.