List of Plot Points

This is a list of elements in B3313 that advance the so-called "plot" of the hack, although said plot is mostly allegoric and up to interpretation. Nevertheless, most of these elements seem to hint at the presence of an evil being (the personalization AI) that keeps the Mario brothers hostage in his "realm", the castle's internal plexus.

The lone Cosmic Clone
In Scary Sewer Maze, venturing through the maze the right way will eventually lead the chosen Mario brother to what looks like a Cosmic Clone of Mario sitting next to some "building blocks". on a checkered platform with a "corruption". If you approach it too closely, it "awakens" and leads to either the player dying or the game freezing.

In Peaceful Sewer Maze, reaching the same location, the player can see several blue puddles surrounding a normal-looking checkered platform with an unknown object on it. One of its faces, though, resembles the Cosmic Clone's face. This might mean that it's in hiding at the time of the player visiting the area.

Faceless Mario's curse
In the Purple Plexus, the bob-omb buddy at the door of the Purple Upstairs greets the player by saying: "good thing you picked this way". And indeed, by going through the hallway to the right of the plexus logo, the player will be met with what looks like a Mario "statue", although by going around it, it becomes visible that it has no face. By approaching it at the right angle, Mario/Luigi gets damaged by 3 units when touching it, however, if the player is not so lucky, the game briefly freezes and they will become surrounded by several copies of the entity, along with their "leader", a faceless head (possibly a reference to Mario Teaches Typing, or the title screen itself). Interacting with the door the Marios are facing will cause the "eel" sound effect to play in a jumpscare-y manner, while the action itself and going basically anywhere other than letting yourself be attacked by the faceless army's hitboxes will get the player out of bounds and result in death.