Danny Boyle's so-called reinvention of the 'zombie horror' genre is neither a reinvention nor about zombies. Instead it is a fascinating study of the nature of human survival in the face of a deadly and grotesque plague which turns its victims into blood-spewing cannibals in under 30 seconds. That is, until it degenerates into an incongruous morality tale with an action movie climax that abandons all that came before it.