These are the different type of zombies! Grade 4: a plain, old, simple zombie who is easily killed with a pistol Grade 3: a zombie who’s a bit stronger and smarter than a grade 3; can easily be taken out with a rifle Grade 2: a zombie who’s smarter than both grade 3 and two zombies; can sneak up on enemies and make stealthy kills; a sniper or shotgun should be able to do the job Grade one & special grade: Smarter and stronger than all three of them. A nuke could take out a clump of them.