Cute pixel art minions and an interesting mechanic using dice values to apply bonuses! I imagine you could take the concept even further by allowing players to manipulate the dice values as well.
As for the dice, it's not very clear that one of the three isn't the actual value.
I would also amplify the visual feedback for selecting dice, right now, it's pretty hard to tell which die is currently selected. And maybe display card descriptions on hover rather than on click would be nice.
I ran into a bug on the last floor where the game got hardlocked during combat resolution.
Good job !