yea, it's all about balance! :P
More comming thought!
Noted and the work is in progress!
The boss is killable, we just doesn't have the animation to see him getting killed over bullets (he gives a lot)
He is the reason why normal zombies are easy, they are juste there to make you bullet to kill him
We have mostly increase most of the feeling, but we still have a stuff to do to.
Thanks for the reply! :D