Both films take place in high school settings and feature unstable characters. They have similarities in their lighting, color schemes, and classroom settings. However, the films differ in that The Day It Ended focuses on the suicide of an unpopular character named Chelsea, while Murder by Numbers involves the murder of an innocent girl by other characters. Additionally, The Day It Ended is set in Britain while Murder by Numbers is set in America, and it only has one main character compared to multiple in the other film.