Texture and camera test. First build with a maze randomly generated from a seed that you can recover to replicate the level, using a tiles system to draw the walls. The camera can change its FOV and move around the maze in order to test everything is how it is supposed to be.
Concerning the storyline, the main character could be a test subject that doesn't know he is just the entertainment of some people who bet how long he will survive or how far he will reach. We ear their voices between the levels, learning about them by this way.