An optional subplot within the fictional game involves a drowned cat. You can skip it by not interacting with the goblin camp in Havenwood's outskirts. (There are no important interactions to be had here.)
Loading 'torus', 'donut', or 'erase' leads to a surreal sequence that ends in a loud, fullscreen hellscape. Some objects stop/start music when approached, some text/images flash briefly on screen before disappearing, and there's the odd loud noise here and there.
Possibly. Two of the (fictional) developers speculate that a third is suffering from PTSD, worry that he might be dangerous, and note that he keeps a gun under his desk. One secret area depicts a mass shooting at the (fictional) development team's office.
ARG elements. The game never directly acknowledges the player, but parts of the plot can only be accessed by doing things outside of the game, and the narrative suggests that something may have broken out into our world.