This is so, so good.
Everything works so well here. The score and sound design complement one another brilliantly. The ghastly moans and gasps of the undead are very unsettling. They’re used to precise effect, alerting us to the presence of the living dead before showing any onscreen - if any are shown at all.
The commentary on ecological disaster is terrific, and it’s aided by some more interesting depictions of authority figures and their inherent flaws.
Highly, highly recommended.