I don't really post reviews for TV series or movies but I have to for this one. I was disappointed with season 1, and I won't bother watching season 2.
The following flaws I noticed in Black Summer:
There is no character development, therefore no background information was given about the characters. This makes it difficult for the audience to have any emotional attachment to the cast.
Very poor dialogue, there is no effort by the survivors to try and understand each other. For example, Sun doesn't speak English and Ryan is mute, the other survivors don't express confusion or concern when these characters are communicating, although they seem to magically understand Korean and sign language, which just makes things unrealistic.
There is weak emotional responses from the survivors, when a character dies no one was grieving they just seem to continue like normal, or the camera views in on their faces while tears run down their cheeks.
The characters have no survival skills whatsoever, they are in an urban area with shops and cars but they don't look for food, water, transport or even guns. They don't even think of raiding the abandoned houses for supplies.
The characters have no experience with firearms, since they are civilians and they're relying on only one character (Spears) to protect them with a pistol, but when they finally get guns they all start shooting like professional soliders. This just continues to make things unrealistic.
The army was apparently bombing the zombies but no explosions, blown-up zombies or destroyed infrastructure could be seen, which just makes the show unrealistic again.
The final scene in episode 8 is terrible. When Rose gets to the stadium to find her daughter the army are nowhere to be seen, her daughter is just with some random survivor, and as the daughter is running towards Rose the camera stops rolling before they can embrace each other.