Hypersudoku

You've got a grid of 9 x 9 squares. Your task? Fill in each square with numbers 1 - 9 so that the numbers in each row, column or 3 x 3 group do not repeat. The 9 groups are surrounded by thick lines. This game is similar to sudoku, except that there are extra 3x3 regions where the numbers must not repeat. The faster you finish the game, the higher your score. Click the hint button when you are stuck, but you will suffer a time penalty when you do so. Have fun with Hypersudoku!