Ultimate Sudoku Collection contains several variations of Sudoku game. Sudoku basic rule: Fill numbers in the board such that every row, column and region contains one occurrence of each number. Features: – Beginner, Easy, Moderate, Hard and Expert difficulties for every game type – Tons of puzzles guarenteed to have only one solution – Easy note taking – Autosave the process of unfinished levels – Record best completion time for each level – Hint feature – Achievements Current Game Types: – Basic – Gattai-3 – Gattai-3 Diagonal – Gattai-3 Anti-Diagonal – Butterfly – Sohei – Flower – Samurai – Samurai Jigsaw – Samurai Diagonal – Samurai Anti-Diagonal – Cross