Start out with the solution for beating the game with the Necroa Virus
The achievement requires the Autothysis symptom and Liquefactive Necrosis ability.
When you are ready to activate the zombies start adding the following symptoms
Insomnia
Fever
Photophobia
Delirium
Cytopathic Reanimation
Anaerobic Resuscitation
Enhanced Motor Control
Peptide Surge
Acidic Reflux
Naja Mortis
Autothysis ***
And these abilities
Regenerative Activation
Ambush Predation
Liquefactive Necrosis ***