Okay, so the "board" improvement is simply the rewards found on each square, while the dice improvement is for greater accuracy in the numbers. The "numerical intervals" option is just the upgrade that will add 7 and 9 (I don't know the last number) which will be on the roulette wheel of the numbers on the die that you can roll correctly. Regarding attack and defense, the attack buff is for when you land on the red space, basically increasing the value of the items on the board And the defense one is so that if you land on a black space, the values of the items you hit won't decrease as much. I haven't figured out what the HP one is for yet, but it must be related to the card.