Episode #1.1 - S1-E1
Other mistake: Kang-bae runs up to the store manager with a trolley to stop him slashing Weol-ju with a knife. When the manager falls backwards into the trolley, he is holding the knife in his hand and then drops it on the ground. His hand is positioned towards the back of the trolley (where the handles are), but the knife that fell out of his hand lands on the ground in front of the trolley when it should have landed towards the back of the trolley. (00:48:20)
Other mistake: Jesus leaves his home with a double barrel break-action shotgun and an ammunition belt holding extra shot-shells. In the next scene Jesus is walking in the street with the shotgun and no ammunition belt, it magically vanished. The shotgun only has a capacity for 2 shot-shells, then it needs to be reloaded, or it can be reloaded after one is only fired, that procedure is called a top-off. He fires 1 round at the mayor and two inside Elena's home which makes three. He never reloads. (00:32:50 - 00:34:40)
Episode #1.7 - S1-E7
Other mistake: Surveillance cameras are shown on monitors when the mass panic kicks in even though any chip-dependent electronics shouldn't work in the game world (previously stated by Chotu). (00:08:20)