Although there's many flaws in the series and it's not exactly like the webtoon, but I appreciate the production team, the director, and all the actors + actresses involved in this series (inclusive of the zombies).
It's not an easy job to act as zombie with that movements. My fav zombie is the one crawling like Sadako.
CGI nicely done, like real. School setting also looks real, make up nicely done too. Got blood here and there (expected from a zombie genre) but not excessively, just enough to show people bitten, injured, etc.

What I like:
1. The chemistry among the casts
2. The moral of the story, not about zombie (yes you need to survive from zombie) but the series remind us the most important thing, like what On Jo father said : to be healthy. The story also reflected today society, people will do anything in order to achieve their own goal (selfish), in this story is to survive once will sacrifice others. In today society is not a "physical" killing, but emotional backstabbing is also equivalent to physical killing.
Don't betray your partner, as you 're the one will die LOL... happen when Min Ji left Hyo Ryung when they are partner to run through the forest and at the end she's the one who died
3. The pacing is good
4. Great acting, especially Gwi Nam

The downside:
1. Some scenes are just too unrealistic, example On Jo father suddenly appear in front of her, he has the key to the lock door?? No sound of breaking the door and the door can suddenly open? Then afterwards why he need to lock himself with the zombie? He also can run and lock the gate from outside...
The never ending arrow supplies...
The zombie can bite fingers too right? so many hollows especially when trying to escape from the gym room...
2. Can't really understand why Ji Su only changed to become a zombie after beaten up? The father already injected the virus long before, but why the effect very slow? And also On Jo was scratch or bitten by the first zombie, but she is ok??
And some others quite not logical scenes...

But despite of those downsides overall it's enjoyable to watch (for me at least). A lot of talented young actors and actresses.. Can't wat to see their future works!