This deck is intended for multiplayer casual play.
All common creatures 3 1 drops 1 2 drop and vengeful dead as a finisher. Early game is usually creature/clamp repeat for massive card advantage discarding the vengeful deads and excess. With that card advantage comes mana advantage via cabal coffers and dark rituals. Use the festering goblins, syphon flesh and grave pact to keep the board free of creatures so you don't get eaten alive. exsanguinate gives you a life advantage so the shepherd of rot's don't kill you. zombie apocalypse and sac as a finisher. Army of the damned can be a finisher on its own as well.
Every life loss effect in the deck is global so it kills everyone at the same time unless there is a deck with a lot of life gain, those decks are the easiest to counter with a grave pact however.
The deck tends to work fairly quickly and win most of the time.
I have considered gravecrawlers im just not sure if its necessary considering their cost. For the most part the clamp gets me more 1/1s to kill, i mean if i had a gravecrawler I wouldnt have to use Zombie apocalypse because i would be killing off the same creature over and over. Still debating.
You could try to work in Gravecrawler since you'll be sacrificing zombies, and maybe Endless Ranks Of The Dead could either pair with Army of The Damned or replace it.
i know its not a zombie, but Blood Artist gains you life and pings and hits the field earlier.