Sudoku Free is a number-placement logic-puzzle game. The player's main goal is to win thousands of Sudoku games to earn enough stars to unlock milestone titles and stunning, peaceful pieces of background art. They complete these tasks by placing numbers 1 through 9 in the correct spaces on a 9x9 grid without breaking classic Sudoku rules.
Sudoku requires that a player never repeat numbers within a column, row or sub-grid or at any point where sections overlap on the grid. It presents the player with a mix of empty and prefilled spaces. The player must cross-reference the numbers across sections and then accurately guess the correct positions of the missing numbers.
When the player guesses correctly, a selected space turns blue behind the number. A wrong guess highlights a space with red. The player also loses a red heart in the upper-left area. They can only guess incorrectly three times.
That said, the player receives several assistance tools below the grid, including classic pencil and eraser options. If they have enough coins, they can use the Open Number button to reveal the correct number for a selected cell. If they use the Show Move tool, the game randomly reveals a correct number with a green highlighter.
Sudoku Free starts with a mountain valley scene. After the player completes 5 levels as a Newbie, they receive a new title. Once they earn 10 stars, they receive another title and access to a new backdrop.
The game features four difficulty levels (i.e., Easy, Middle, Difficult, and Expert). The player earns the most stars per game by always playing at the Expert level. If they collect 2,225 stars, they receive the highest possible title of Emperor. Other titles include Student, Master, Sage, Guardian of Knowledge, Conqueror of Mysteries, Legend, Wise Mentor and Absolute Champion.
