It might not be enough 
So after the first door was unlocked, I had purchased a 1911 then accidently bought another when I was trying to buy a grenade I think, and it turned out the option to keep buying it never disappeared by some bug, so I spent a while just farming up points to convert into an excessive amount of ammo
Bro’s 1911 be like:
unironically, " that’s the play ".
use 1911s until bosses starts showing up.
use giant rooms rather than narrow corners, and voilà.
much more efficient rather than ending up with no ammo because you use them on default zombies.
as well as use the japanese sword or german club for lone zombies apart from each other.
Pistol is better than sword because you will get +2 points for headshots