Continuity mistake: The amount of blood on Allison blouse decreases after Vanya cuts her throat.
Other mistake: When Harold goes to kill his father, we see his dad on the seat moving each time we hear the hammer, but if you look at his head, you don't see anyone hitting him at all.
Continuity mistake: Number Seven is shown in a flashback to be breaking glasses using her powers. She breaks all of them in sequence except one. The angle cuts and the remaining glass has disappeared.
Continuity mistake: While Cha Cha is looking for Hazel at the donuts place, she takes a look and Agnes is hugging Hazel around his head but in the next shot she is not.
Continuity mistake: While Leonard talks with Vanya on the street after she gets mad at her brothers, the sun changes between shots.
Number Five - S1-E5
Continuity mistake: While old #5 is talking with the lady in black, the sun changes between shots.
Continuity mistake: When Luther punches through the armoire, most of panel falls off when he pulls his hand back. But in subsequent shots, there's just a hole in the panel.
Continuity mistake: When Vanya boards the bus, the bus number is 2432. When she sits in the back, the rear window has no number. When the rear window is shown the second time, there is a bus number, but this time it's 7200. (00:19:27 - 00:20:53)