Sudoku: The Puzzle Game That Boosts Your Brain Power! This app not only offers a fun and challenging game, but also has a unique feature that improves your overall culture - City Cards! As you solve puzzles, you unlock virtual city cards that give you interesting information about cities around the world. This will not only improve your logical skills, but also enrich your knowledge of our world! Download Sudoku now and start solving your way to becoming more knowledgeable.