Seeing an unmarked casket in the open like that is very weird, and it seems that the inverted pyramid house doesn't have any official lore behind it. Also there's a room up at the top floor with a chair and camera inside of it, could that be a potential explanation to what happened to Zane and Deloise?
I was looking through this map a lil bit ago and with the music and that room upstairs it's just so creepy I want to know if it all pans out into a story tho