Killer Sudoku - Brain Games is a free Sudoku puzzle game that is available for download on the App Store. This game is perfect for Sudoku beginners and advanced players alike, as it comes with four difficulty levels - easy, medium, hard and expert. With over 5000 challenging puzzles to choose from, you can enjoy Sudoku games anytime, anywhere and improve your logical thinking, memory, and brainpower.

The goal of the game is to place the numbers 1 to 9 in each grid cell, making sure that each number appears only once in each row, column, and mini-grid. To help you solve the puzzles, the game comes with features such as Pencil Mode, Highlight Duplicates, Intelligent Hints, and Long Press to Fill Quickly. You can also turn on/off sound effects, highlight identical numbers, and use dark mode to protect your eyes.

In addition, the game offers daily challenges and trophies to be won, auto-save, unlimited undo and redo, and the ability to share your progress with your friends on social media. The app also has an intuitive interface, easy control, and a clear layout, making it the perfect time killer and brain teaser. Overall, Killer Sudoku - Brain Games is a must-have app for anyone who loves Sudoku puzzles and wants to keep their mind sharp.