Hidden in various chapters are 'Nightmare Levels'. These are secret areas that, when interacted with, transport BJ into a retro-styled, pixelated version of the original Wolfenstein 3D. Each Nightmare Level is a full, playable level from the classic game. Completing them is a fun nod to the series' roots and offers a unique break from the main game's action. They don't offer direct rewards for the main campaign but are a fantastic Easter egg for long-time fans and a challenging diversion. Look for a bed in specific locations to access them.
