Anxiety can be the hidden engine of the level, not just a mood—think of it as a variable that feeds the game. As the player’s heart rate spikes, the world tilts: corridors get longer, shadows shift, and the AI’s hearing range expands. Add a subtle, real‑time audio cue that mimics a racing pulse; the louder it gets, the more the lights flicker and the enemy’s footsteps echo. Use timed puzzles that only resolve when the player calms their nerves—maybe a pressure plate that only activates when a breathing meter stabilises. Keep the mechanics tight, so every breath feels intentional, and let the environment react like a living, breathing partner in the stealth dance.