This person(?) has the power to swap minds with what appears to be other versions of himself who all see the world in different ways. Where one pair of eyes sees a bottomless pit, another might not. Where one sees a locked door, another sees a key. To change perspective is to change reality!
Combining these "realities" allows him to progress - or to at least do something that resembles progress - however this new found power leaves him deeply confused. Who is he? Why does he have this super power that doesn't make any sense? If he's swapping between bodies which body is really his? Why does he keep having to pick up keys and unlock doors? Where is he going? Is he even going anywhere? Does he even exist? What is he looking for?
The answers to some, all and none of these questions will be probably definitely not be maybe found by playing the game.