Factual error: Looking at a nuclear explosion that close will burn your retinas irreparably. One can be blind 30 miles away, just by seeing the flash. The little girl at the start is looking directly at the explosion when it hits, and continues to watch.
Continuity mistake: When Agatha is talking to Herbert at the police line, the position of her arms varies over several shots.
Lost/Found - S1-E1
Factual error: A mechanic is outside the ship repairing the shields. A fire starts, and the fire burns just as it would in an atmosphere. Impossible in the vacuum of space.
Second Date - S1-E2
Continuity mistake: At the deli, Jane orders plain bagels with cream cheese. When she gets home, she has everything bagels with lox.
Factual error: Barbara shoots her revolver at the guys chasing them. When she stops and gets out of the car, she opens the cylinder and we see she only has 1 round left. However, the other chambers should still have the empty casings in them instead of being empty.
Factual error: Abby gets out of the train via the driver's door. You see a front view of the train. The number on the train is 321434. This train runs on overhead lines, and it is being shown as a Gatwick Express train from Gatwick Airport to Victoria. The railway from Gatwick to Victoria has a third rail conductor, so this Class 321 train would not have been able to move. (00:50:02)
Episode #1.5 - S1-E5
Continuity mistake: Toward the end of the episode, Pearce is cornered on the roof as he stands near the waiting helicopter. He puts his rifle down at his feet but never moves. When he lies flat as ordered, his rifle is now well behind him as he is now much further from the ledge.