Nice game! Really enjoyed the concept and found myself trying different tactics for how to reach the highest numbers. I know that filling the board fully has the highest potential but you have to go about it in a strategic order and you might just end up rerolling all your good numbers into bad ones.
I Found one bug on my second run which was that the re-roll rule was inconsistent, the dice I placed adjacent to other dice (starting from the left top-most corner) didn't cause a re-roll.
This bug was more of a feature on my end though since it meant that my lucky first 6 never got re-rolled!
//Maxi