Don't Look Down is a simple puzzle based around the players natural curiosity.
The puzzle is a large room with a low ceiling, solid walls and a floor covering a long downward tunnel. There is a purple panel indented in the ceiling in the middle of the room. The inside of the panel is not visible unless the player is directly below it. When they are they can look up and see the white text "Don't Look Down" on a black background.
After this text is observed, the floor of the room is converted into a horizontal Eye Wall with a short reaction time. This means if the player looks down, as is their natural curiosity, they will look at the Eye Wall and cause it to disappear. The player will then fall down the tunnel.
The tunnel is a very long fall, it lasts for about 10 seconds. The fall is the longest in the game and can be quite a shock for new players but as there is no concept of fall damage in the game so there will be no harm done in landing.