Killer Sudoku - Puzzle Games is a logical number puzzle game that offers a challenging twist to the classic Sudoku. The game is designed for both beginners and advanced Sudoku players, with thousands of puzzles to solve. The game is available for free on iPhone and is developed by Guru Smart Holding Limited.

The game requires players to fill the grid with numbers from 1-9, just like in classic Sudoku, but with the added challenge of ensuring that the sum of numbers in each cage (areas surrounded by dotted lines) is equal to the number in the upper left corner of the cage. This is where the game gets interesting and much more challenging than classic Sudoku.

Killer Sudoku has several balanced difficulty levels that cater to both beginners and advanced players. The game also offers additional features like note-taking mode, auto-check for mistakes, and daily challenges that offer special trophies. The app has a clean and intuitive interface, making it easy for users to navigate and play. With its perfect selection of different levels, Killer Sudoku is a great way to enhance your logical ability and learn more Sudoku skills.