The visuals are simple but work. The sound effects are fine but i feel like the game lacks some music.
As for the gameplay, I feel like there should be a delay before the die starts rolling because otherwise the first roll that is displayed is useless (since it is replaced by another one even if you do a quick click).
Also, I feel like the fact that your attacks are randomized each round doesn't add much besides confusing the player. Indeed, having to learn which number does what each time you replay the game is not fun and does not really add much to the gameplay.
Also, the healing cloud feels useless since you have to be inside it to heal up but you can't stay there since enemies are coming for you from all sides.