Game is pretty funny if you like sudokus.
But, just maybe, it gets more visually apealing if the clicked dices get a different (less saturated) collor.
Also, you can put 3 or 4 fixed dices per game, so it becomes harder to Cheese by Playing like:
1,2,3,4,5,6
2,3,4,5,6,1
3,4,5,6,1,2 ... and so on