Killstreaks

Players that kill multiple enemies get items. These items get better with more enemies killed, eventually looping and giving the same items. Players with hardline require one less kill for killstreak rewards.

Zombie Killstreaks
Mobs continue to get killstreaks even if killed. For example, if a zombie kills one survivor and then dies, the next time they kill a survivor, they will get two mushroom stew rather than another porkchop.