Unlocked the alternate ending/secret ending...
Not sure what to make of it.
My thoughts are generally that the game is conjecture about the nature of free will. Someone else went into some detail in this thread about it, and that sounds pretty reasonable.
There's so many small hints that you can think a lot about:
- In the film development secret room early on, what is the significance of seeing the photos of the limb monster?
- Why does a photograph develop that is a scene fro later in the game?
- Why does that father and son character watch you complete one of the water puzzles?
- Why are natural creatures drawn to you like the chicks or the fish in the water, but one particular unnatural creature -- the water monster -- is seemingly not on your side.
- In the gravity water puzzle room there looks to be a camera device setup outside the window, which is similar to the camera devices pointed at the test subjects near the end of the game (particularly that giant lanky creature that is seemingly rubbing blood on the wall)
- When you become the limb creature, and go back to those study areas, the tall lanky one is gone... But the other creatures are still there being drones (well, one other, in the room with the printer machine).
- Why is there an exact replica model of the ending sequence of the game in one of the science laboratories?
So many more questions...
Also in the Trailer you get a great view of this area, the working lab, before it all seemingly went to hell:
https://www.youtube.com/watch?v=k-2wlQM8BgE
Compare this to how it is right before you get to the big tank... Now, should we assume the guy sitting on that hospital bed in the trailer is the barely moving creature that you see in this area in the game? It's pretty clear that the E3 2016 trailer is set at a time before the events of the game. Even without the character "interfereing" things are significantly worse, out of sorts, test subjects becoming those humanoid sponges, etc.
So, with relation to free will, you as the player take over these human sponges with your mind and make them do things to you. You can then use those human sponges to control other human sponges. Meanwhile, you, as the player, have no real idea why you're doing any of this. Later you can control those humanoids without any devices, and they naturally flock to you and you seem to all be thinking the same thing... E.g., when you want to go up, they all life you up, when you want to open something, they all open something with you. Finally, something triggers all of the scientists to know that you're on your way and they all group around the giant test chamber knowing that something significant is happening... When you approach, they look at you like "Eh, whatever," and keep their viewing position. They, seemingly, know that you're coming.
BUt then when you do break in... And you start dismantling the controls around it, they definitely want you to stop. When you start to break free, they flee (except for a couple of them who stay and presumably die).
ANd then just the weirdest part ... That model of the outside of the building, which is also in a viewing chamber of sorts, with a spotlight shining down on the exact place that you die/rest/finish the game. This all seems to suggest that you either don't have your own faculties, that you're destined to reach that point, or that you're doing it over and over again in a Limbo-esque loop (the photographs seem to corroborate this).
Of course, the alternate ending sort of throws a wrench into this. You unplug these power stations or whatever they are, all over the map. Meanwhile somebody or some thing has sealed a chamber off from you and conveniently planted a tape recorder that plays an identical "music" loop of the password that you need to unlock the secret room that... At least you have to imagine, shuts the whole thing down. So who recorded that, how did it get to one of those other areas, and why is it there? Finally when you break in, you see some computer machines and a mind-control device, and when you unplug everything your character just sort of falls over and wilts.
What does it mean? I haven't a damn clue.