The idea is good enough, at least on paper. The presentation of the idea in the game is a little wobbly because there are not enough effects to "illustrate" what exactly happens. For example, you could add a "spark" effect between enemies and dice, so the player would see that the dice make the enemies appear. Also, you can add a "text counter" which will show how many enemies will be on the map depending on the number of the die. That all would help the player understand that those enemies are not spawning randomly, but they are actually related to the dice somehow. So, because of that, players will enjoy your game much more with an understanding of what's going on.
Overall, good platformer. I would change controls just a bit (+ 0.5 jump height). Besides that, good prototype! I wish you will continue to develop it in future