The objective of the game is to follow the game rule
and fill in the grid. The player will win the game
if all the digits keep with the game rule.
Table: 6*6(36 grids), 9*9(81 grids)
4 Levels: easy, medium, hard and evil
6*6 board: 800 build-in boards for each level
9*9 board: 1200 build-in boards for each level
Can pause and continue the game
Counter function, Hint function, Save/Load function
and solution function
Sound effect