The mod adds a dynamic "Sanity" system. When the player spends a long time in darkness, underground, or amidst night fog, their sanity meter drops. Hallucinations begin: the player might feel like someone is running up behind them, see false monster silhouettes that vanish when targeted, or hear whispers in their headphones commenting on their in-game actions (for instance, a voice whispering, "Why are you digging down?.." ).
