SuBundle Sudoku

Have you ever gotten frustrated with a tough sudoku grid? Have you outgrown your medium rated sudoku book? You'd like to buy sudoku books for your friends, but you're not sure what level they plays? You feel like playing an easy grid or you think you're good enough for the next level, but all you have are medium rated grids. The grid on today's newspaper is just way too easy that it's not even fun. If any of these situations apply to you, then this book is for you. The name of the game is SuBundle. With the help of key cell(s), SuBundle puzzles have up to eight difficulty levels in each grid. Potentially, SuBundle is a more challenging game, but most are just similar to Sudoku.