Sudoku by MonkeyBrains is a full-featured, free iPhone game offering thousands of 9x9 puzzles with varying levels of difficulty. Whether you're a casual player or a seasoned Sudoku enthusiast, this app caters to all with its six difficulty levels. The game allows you to enjoy endless hours of challenging fun, with features like auto-resume, hints for when you're stuck, pencil mode for multiple numbers in a cell, and a guess mode to help tackle the toughest puzzles.

Moreover, Sudoku by MonkeyBrains lets you keep track of your progress through easy-to-view statistics, making it a well-rounded and engaging choice for Sudoku lovers on the go.