A nice twist on roll of the dice, it definitely fits with DnD because of the amount of dice rolling associated obviously. Though I wills ay the d20 only doing explosions was not what I expected. But it does make sense based off what was said in the description. It would be very cool to see other effect sand such from the D20. Not sure where those would go but it would definitely mix it up a bit.
Though I wills ay the D20 insta killing was not what I expected but was incredibly fun to abuse. Maybe some sort of kick would be interesting ? I feel like it would be very abused, but very fun to kick the d20 through hordes.
Also I feel like randomizing where the enemies spawn more could be interesting. Where the dice just show how many WILL spawn and then some spawn throughout the map. Cause currently most of the time I just walked away from the dice and shot them adown as they walked up to me. Zombie style.