If I had time, the way the game would work is as follows:
- There would be multiple humans throughout the facility
- You could attach/remove parts to yourself (the black thing)
From that you can do a lot of things, ie the "IOU A HUMAN SCANNER" sign was a room where a scanner would check if you had a living human head and living human legs (body parts attached to you come back to life, as seen with the legs). Then you can do weapons, different legs, just stacking up more body parts so you get different reaches and so forth.
But yeah, the game's supposed to be you playing as the black thing - the human is just an intro and teaching the controls.
EDIT:
In this version, the way it's supposed to go is the human gets blown to bits, you become the black thing and climb on the legs.
From that, you use your tentacle to drag the dead human's torso with the hand, or just drag the hand, to activate the hand scanners and get to the "ending".