Very good in the gore/violence genre. We'll just turn a blind eye to the fact that it seems to be a virus that was already pretty spread, but just suddenly mutated, in millions of persons at once, all over the country, in a matter of hours or maybe even minutes.
Contrary to most zombie-like stories, people here are conscious, they just can't control their very sadistic urges. That makes them smarter, and allows for a main antagonist (the old guy hitting on Kai Ting in the subway) throughout the movie.
It is very violent, but reasonably gory. Yes there is blood, lots of blood, but it's not spraying ridiculously everywhere and quantity is normal for the number of victims. The first attack is very graphic (burning oil thrown at face and skin being peeled of), but that's about it. After that there are some stabbing, but the most graphic violence always happens off screen, no close up on body parts being ripped off or internal organs being removed or other stuff usually depicted in this kind of movie.
The balance is well maintained, managing to be extremely violent without being too ridiculous or too disgusting.
Only intentionally comical part, as a critic surely, is the government intervention, for a little laugh break in the middle.
Another good point in avoiding the genre clichés is that the main characters do not act completely stupid, most of their action are rational and compatible with survival.
Junzhe part is not really interesting until they meet again, the main story is Kai Ting's.
The meeting with the scientist was quite original, bonus points for the babies part. With the (probably mandatory now) jab at people not trusting doctors and fake news.
The ending, with Kai Ting being miraculously [spoiler]immune, even when injected directly[spoiler] but despite that being [spoiler]killed off screen by the military[/spoiler] was a nice final touch.
