Hi! Cool, thanks for playing! Yeah, the fireball should maybe travel faster than the player and maybe i'll adjust that after the voting ends :)
I watched the stream and it seems you're panicking a lot when the enemy apears and kind of just stand in place instead of moving outside of the shadows attack range. He only does damage for the 3-4 frames he's completely visible and doesn't move once he starts his animation so you should be able to outrun him once he appears. One way to cheese him would be to just run back and forth on the floor with a fireball on top of the player