Something is wrong with ZM 4

First of all you can't damage Manticore with spas, and strangely i get some damage with pistols (raging bull) on his butt.
yeah... its funny, but that how it is.

4 stars bosses give like 1-2 attack?
we(players) use to end up games with full 90 attack and probably full in blaster skill you pick.
now you are happy if you finish with 50 attack and some blaster skill.