Zombies in the War of the Dead take several forms:

Shambler

Your standard slow moving, uncoordinated, Night of the Living Dead Zombie. They make up for their clumsiness and slowness with numbers and determination. They never give up ever and will follow you until they catch you (or something else captures their attention).

Sprinter

This is more of your Resident Evil / 28 Days Zombie. Quick, cunning and powerful. They are really fast and really deadly.

Infected Newborn

These are actually alive, but their mother getting infected changes them into a quick, ravenous beast whose size counterdicts their speed and strength.

Living Dead General

The worst of the worst - these are intelligent living dead with the ability to guide other forms of undead and make them do their bidding.