How Killer Sudoku Works
Killer Sudoku uses normal Sudoku rules plus cage sums. A cage is a connected group of squares with a small total in the corner. The numbers inside that cage must add up to the total without repeating inside the cage.
Killer Sudoku Difficulty
Easy uses smaller cages and more available help. Medium is balanced. Hard and Expert create larger cage groups and limit hints, so each solve depends more on arithmetic and deduction.
Killer Sudoku Leaderboards
Completed Killer Sudoku games save separately from classic Sudoku. Compare runs by difficulty, score, time, mistakes, and hints used.