For people having problems with ammo in the grace sections:
Try to kill few enemies as possible until you get 1 or 2 gun power steroids, that way you are gonna be more efficent with bullets.
Whem you aim, wait for the reticle to change shape with the dot in the centre, you do more damage, don't just spam the button.
1 bullet to the head or leg, melee prompt to ko, then a couple of bullet to the head (no spam, wait for the reticle) is the easiest way to kill zombies, using the knife while they are down can probably save you something aswell.
If you manage to get a melee knife and have some bullets to spare, maybe killing the butcher is not a bad idea, he indirectly give you something than enhance something that let you save some bullets, not gonna say more.
Beginning is rough but after a bit the situation get much better when it comes to ammo