A few things that seem odd to me (spoilers)
1. On-Jo's dad So-Ju. His ability to dodge multiple bullets from multiple assault rifles while running in the open was a little too much. That could've been done better with little effort.
2. I didn't understand the decision to cut phone and internet to Hyosan. Were they thinking zombies were gonna call them up? The only thing they did was cut off anyone on the inside who was trying to call out for help.
3. How many times did these kids stand around and watch someone change into a zombie before they took action. Geez...…. They seemed more worried about who was in love with who.
4. Na-Yeaon, the girl who killed the "welfie" Gyeong-Su. She at one point was collecting food to take back to the group to make amends. But on the way, she runs into that bully Gwi-Nam and gets suddenly jacked. It would've been cool to see her make it back, give food to the group, and see if she could make amends. I think it was a missed opportunity in writing.
5. Message to Class President Nam-ra: If you see someone wiping zombie blood off a mop handle and putting the hankerchief in their pocket, don't be afraid to speak up.
6. Time was spent in multiple episodes showing So-Ju trying to make his way back to his daughter On-Jo. He makes it and suddenly dies? And dies for no reason? There was no reason to stay on the other side of the gate at the tennis court. All of his storyline seemed a waste of time.
7. The bully Gwi-nam was such a reprehensible character. I think we were robbed of seeing him get what he deserved, which was a brutal death. All we see is him being blown down a shaft with Cheong-San. But my guess is that it was a little vague on purpose. He's the type they might want to keep around in case there's a Season 2.
8. I don't understand why the Commander committed suicide. He had no choice and actually did the right thing by dropping bombs on Hyosan.
This is no "Kingdom" or "Train to Busan", but it was decent enough.