Sudoku Numbers

What is this game about?
You have probably seen people at airports and on trains filling out empty table on booklet pages with numbers. Sudoku is the new popular logic-based number placing single-player game.

How do I control the game?
You play by clicking the empty cells and typing in a number. Put a cursor in an empty cell and enter a number on the keyboard. If there is the same number in this row, your cell will become red that means a mistake. If there is the same number in this column or in the group (square) it will also be marked as red.

How do I win?
The goal is simple, manage to place fill all empty cells with numbers and you will win.

Gameplay tips:
1) Consider that fulfilling one square field immediately will end up invalidating the rest, try not focus on just one. Instead distribute the missing numbers one at a time throughout the entirety of the board;
2) Sudoku games are very hard depending on the density of the board. Go for smaller boards first to get used to the gameplay;