Continuity mistake: A vast majority of the movie occurs over the course of a single day, so it would be expected that Becky's hair stayed about the same. However, there were frequent fluctuations in Becky's hair's length, how her bangs were arranged, and color (whether the blue streaks could be seen at all or how much at a given time, and if she had dark roots on the top of her head).
Factual error: Apex, played by Robert Maillet (a retired professional wrestler 6'11" and 350 pounds), forcefully slams Becky (played by 5' tall fifteen-year-old Lulu Wilson who probably weighs under 100 pounds) horizontally with her back hitting the ground from waist-high yet Becky is able to get up with no incapacitating injury that would be expected. Becky also manages to brutally kill him (as well as the three other neo-Nazis).
Continuity mistake: Dominick's tattoo on the back of his head changes from the time he was in the prison courtyard to when he was boarding the bus. The older tattoos underneath were not entirely covered up or removed, blurring the swastika that he had thereafter. The transitions that occurred didn't seem possible - a swastika on top of a circle would not turn into a clear swastika. In ONE shot of the back of his head, the entire tattoo was located higher than his ears while others went lower on his head.