I really liked it. Took a few runs to develop (about an hour and a half) a strategy that seemed to be working (pretty much always filling dice faces with damage and one die with healing + warping back to me). It really made me wanna try different builds, so I believe it in part achieved it! However some of the faces felt too weak (2x exp and ice) and after a while it becomes a tad repetitive.
I missed a pause button, not sure if there was any but I had to stop playing for a while and just had to give up a nice run. Also, the level up sequence sometimes tricked me. It takes a while between seeing the level up text and actually going to the choose die face menu, and oftenly I'd end up clicking somewhere I wanted to fire but it would compute a click on the die face menu. Maybe going to the menu and freezing player input could avoid that.
The enemies projectiles going through dice also made me take damage without actually seeing it, but I'm not sure if making projectiles not pass through dice could make the game too easy.
Music and effects were okay. I liked the song but it got a bit repetitive after a dozen minutes in. One minor thing, once I died while lightning was enabled, the electric sound remained on forever as I kept on the name input screen. Maybe sounds from the gameplay could be deactivated? It's not much of a big deal anyway.
Again on the balance, maybe making ice area of effect bigger could make it more useful. It seemed to have the same area as fire but fire you could really feel it damaged enemies. Ice didn't feel like slowed enough and barely did damage. Also, I had no clue how much health the big fatty mushroom had, I never managed to kill it directly, just running around and hoping enemies would roll the dice accidentally in the way.