In a retrospective article detailing the making of Chapters 3 & 4, developer Toby Fox stated that the sequence where Spoiler:the SOUL travels alone throughout the Holiday Mansion went through several disparate revisions during development to "make you feel like it wasn't wasted." Fox stated that he initially conceived "a Rube Goldberg machine, involving many crazy parts" which the player would need to utilize in order to manipulate character actions. Subsequently, this was replaced with a sequence where the player utilizes a model train set spanning the whole of the house. When this didn't work, he conferred with personal friend and Homestuck author Andrew Hussie, who suggested a puzzle requiring the player to complete a bust parodying Macaulay Culkin's pose on the theatrical poster for the 1990 Christmas comedy film Home Alone.

Ultimately, Fox opted for the final game's approach, in which Spoiler:the SOUL simply navigates the mansion vents to spy on various characters, after realizing that "just focusing on the story and atmosphere is the best." Despite this, remnants of the early ideas remain in the released version of Chapter 4. The tail end of the sequence includes Spoiler:a scene in which the SOUL has to manipulate Noelle and Susie into capturing it and moving it into the living room and a scene requiring the SOUL to manipulate objects in Dess's closet while distracting Kris. Additionally, Chapter 4's data includes sprites and a functional test room for the toy train, while various sprites associated with the final sequence feature the phrase "homealone" in their filenames.