These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Time Fcuk
Brown Note - What this game will cause to your sanity.
Ear Worm - The story mode's very catchy— and very lonely —background music. It starts off as a repeating series of beeps, and becomes a song about half way through.
Madness Mantra - You will be thinking of one by the end.
On a related note, the game doesn't specifically name the player character until later via one of the texts sent by another one of yourself. If you happen to be named Steven and not realize that the player character is actually named Steven, the first time you get a message in which you're called by the name can be quite disconcerting, to say the least.