Thanks for the feedback!
For the boss stage 1.3, the stage was rushed in the last day of jam, and when we did the playtesting yeah it's a bit difficult one and we only beat it in one way, "spam ranged till out of mana then slash slash", if it fails then the bat will spawn and giving player hard time.
We noticed that melee form need a better mechanic because it is literally useless except for refilling mana, and most importantly after seeing all the feedbacks, we should've remove the bat from game.
Once again thanks for playing and for the feedback!