Homestuck gains complexity through iterations, in plot, setting, and character. As the tutorial character, John’s actions are straightforward and relatively easy to follow, which sets the stage for grander installments. John’s plain house and Dad are followed by the increasingly complex circumstances of his friends. John’s ability to combine items across captchalogue cards (1917) is a primer for combining items via alchemy. If a rule is introduced through John, subsequent iterations of the rule will be more grandiose.
So, an observation: John is afraid of heights. When John slips on a staircase, he flips out (2460). When he nearly launches himself into the abyss with the Pogo Hammer, he has to take a nap before he has calmed down enough to continue (2537). Immediately following both moments of vertigo, massive ogres begin to climb toward John’s house (2461, 2542). The eventual fight with the ogres begins after John looks over the roof of his house, into the abyss (2562-3).
All of this suggests that Sburb is reacting to John’s emotional state (fear) to produce in-game content. This is further suggested by a peek we get at some of Sburb’s internal processes (3419):
Here, we have reference to terminology associated with Carl Jung and Sigmund Freud. The terms suggest that Sburb interacts with the ideas in the kids’ subconscious minds (archetypes) and brings symbolic representations of these ideas into conscious reality (manifests the ideas). Like, pipes are Johns’s dad symbol (1974), so LOWAS is covered in pipes as a subconscious reminder of his dad. Or, Dave is surrounded by dangerous sharp objects in his apartment, so LOHAC is full of grinding metal gears to subtly (?) remind him of his awful, awful home.
Even before we reach the kids’ planets though, John’s encounter with the ogres asserts Sburb’s dream-like nature. The “hyper flexible mythology” of Sburb is essentially the same as Freudian dream logic – Sburb caused John’s latent fear of heights to manifest as real, punchable monsters.
But if you look through Homestuck for things that materialize due to emotional events, it doesn’t stop with imps and monsters. It also includes the trolls.