Sudoku Countdown is a free Sudoku game for Windows. It can be played on-line and offline. This software is quite simple. It features a board with a Sudoku grid and a few numbers like the traditional Japanese game. In addition, to make the playing more challenging, there is a countdown clock. We start the game with 10000 points, which will go down as we play the game. We must fill all the emptied number tiles with the correct numbers before we run out of points, otherwise the game will terminate and we will have to start again a new one. If we want to write number 1, we must click the mouse once, if we want to write number 5, we have to click five times and so on. The level of difficulty for this game is medium. In order to play it offline we need to download this software, which is available free of charge from the developer's website. From the program Main Window, we are offered the possibility to add the game to our website for free. We are allowed to turn on/off the accompanying music.