I really like the art! I read some earlier comments so I'm confident you know it would be better to add sound, instructions, and more feedback on everything. Even though you haven't implemented much if any choices for the player to make, I really like it as a proof of concept. With a little strategy to go along with the luck it could be very compelling.
For some reason, probably the shape of the presentation, I was reminded of Backpack Battles and would recommend their demo as a good resource to get ideas on how to communicate with the player how the battle changes as the dice keep rolling.
I really hope you work on the game again in the future. I would love to play it again with more choices for the player to make.