The Walls is a Half Life 2 modification which, though not a simulator, has you in the role of a mentalist patient who walks through what could either be reality or mere imagination. Decide your own fate with the choice you make, but be aware of the one rule. Read the walls. Or you will die. Conceptualised and created by AirWithoutOxygen, with technical support from the community, The Walls has been planned since 2008, and finally is nearing completion. New screenshots added regularly, more information available shortly. Disclaimer: Whatever it may appear, The Walls is a short modification. Do not expect anything of great length. You may, however, expect unnecessary complexity.
You might find that your mind is picturing people from your past. But is it the past, or did you never know them at all?