Based on this, I think I'll increase this boss HP. I manage to beat him with 2 potions left and he has 2000 HP. So I assume 3000 HP would be just enough to be beatable with 5 potions. I haven't tried playing it with a real gamepad, though, so maybe with a real gamepad he is much easier?
EDIT: I did it with 2 potions now. Also I realized that if I want to increase his HP I need to update each projectile one by one
. But yeah, 4000 HP would be more "reasonable"
Also here's a new video of him