Liminal spaces ... a flickering hallway that seems to go on forever, or a pool that looks like it’s hiding a secret, these spaces hit that perfect mix of creepy and nostalgic.

A great example of liminal space images would be pics of empty malls, parking lots, school hallways ... not all liminal spaces have to be scary. As the mentioned r/LiminalSpace states, liminal ...

You move your character around using your keyboard, and as seen in the trailer, you explore eerie liminal spaces and pipe-lined hallways ... the wall into a new creepy area.