That is a really interesting concept. The graphics are really good. I find it enjoyable for 15 minutes until I realized there is really no way of defeating that boss with 999 move. So yeah, I'm stuck. Unbalanced which is understanable in our given time frame.
If you want to expand this further, one workaround to fix the stuckness is to give a way to do an extra action the longer the battle goes. Whether it's a skill, an item passive effect, etc. it just have to be used after some time like a Happy Slash skill that automatically activates after accumulating 10 swords in the slot machine.
It is impressive how much you can do in two days. Good job!