Tetris Online. Falling Sudoku. Original adaptation of the Tetris game. Place the falling numbers according to the Sudoku rules. The numbers 1 through 9 can only be used once in each row, column, or 3x3 region. Empty tiles can be used as a wild card, while gold tiles increase the score. Use the keyboard arrows to place the numbers and the space bar to make them fall. Accumulate points by keeping the Tetris game active.