- Kevin's ability to alter his body chemistry to suit his personalities becomes much easier to swallow with The Reveal that this film takes place in the same universe as Unbreakable, where such superhuman feats are indeed possible. Likewise, "The Horde" (the collective name given to Kevin's malevolent personalities by Kevin and the media) and "The Beast" are perfect names for a super-villain.
- Kevin frequently refers to himself and others like him as "broken." This has much more meaning when you consider this is a sequel and a parallel to Unbreakable, where the main focus is on a character whose power is derived from being unbreakable.
- Hedwig's tendency to curl and walk low, and also the fact that he is shown skating while heavily bent forward in Glass makes sense once you remember that he is supposed to be a 9 year old childlike personality: curling and bending are ways of bringing him to the appropriate height.
- Both the posters for this movie and Unbreakable have broken glass imagery.
- The CD Jacket for the Split score by West Dylan Thordson has a cracked silhouette of Kevin against an orange background. Kevin was originally supposed to be the home intruder at the end of Unbreakable, but was eventually replaced by the Orange Man.
- Using Kevin's full name to temporarily stop The Beast and force his original personality to the surface is similar to defeating a demon by invoking its true name.
- The scene when Kevin's Patricia personality lays flowers in front of the train seems strange until it is subtly implied that Kevin's father died in the same train incident that David survived. The Horde is making a small memorial for him.
- This is confirmed in Glass (2019).
- M Night's cameo becomes this when you remember that he could be the same drug-dealing stadium-goer that David nearly caught. Though he could have gone clean since then.
- Confirmed in Glass, along with him going clean under Dr. Fletcher's guidance.
- Casey's father's death. I know it's stated in the movie that he died of a heart attack, but what if that was a lie, and Casey's uncle murdered him so he could have her for himself?
- The fact that it was Casey's uncle who described how her father died, with no one else verifying that, does lend further credence to that horrifying possibility.