Fun concept but the x4 dice are extremely broken lol, you can basically stall early fights for tons of money and then do x4 then x16 dice to one shot the entire game, reach armor cap in one go or generate even more money (to get dice that have perfect result for exemple). I didn't bother getting a x64 with the last dice cause I could tell the game wasn't expecting me to do that (and yeah, I one shot the last boss with x16 aoe).
Typically you want to avoid reliable exponential increases in your balance =p eitherthat or you need to balance around player abusing it but that makes it impossible for those who don't figure it out. I would remove multiplier dices entirely, or limit them in some way, or replace them with additive dices.
Other than that it works well ^^