Sudoku Serious Sudoku - Tiered Difficulty Blue Easy → Medium Serious Sudoku Portable · 6×9 Full-Sized · 8.5×11 Purple Medium → Hard Serious Sudoku Portable · 6×9 Full-Sized · 8.5×11 Red Hard → Expert Serious Sudoku Portable · 6×9 Full-Sized · 8.5×11 Serious Sudoku - Specialty Serious Sudoku Serious Sudoku Samurai Full-Sized · 8.5×11 Serious Sudoku Serious Sudoku: Ultra Large Print Full-Sized · 8.5×11
