Zombies are good, but you GOTTA have mutants of some kind (lickers, hunters, tyrants, etc.) Try the Strong Zombie, he has a deadly arm, ribcage exposed, falling out guts and maggots. He is a genetically-engineered super-creature who can beat the player down in seconds.
Animations:
https://www.youtube.com/watch?v=vWG0RDeA5ak
Also we're running the August Sale - 50% off all items so what are you waiting for XD
http://3dfoin.com