POINT 1: As shown in the picture, the con.nection between Stanley's co-workers all 'dissappearing' and the event in Portal when GLaDOS kil.led everyone with a deadly neurotoxin.
POINT 2: There are files I found in The Stanley Parable for the Companion Cube and all other related objects you use in Portal, even the portals themselves.
POINT 3: The Narrator points out that the fern you pass by at one point will become extremely important later on. It never does in TSP, but in Portal it is one of the many plants that grew out of control after GLaDOS was defeated.
POINT 4: The building and atmosphere in both games is shockingly similar: the computers are the same, the desks are the same, and both have huge underground rooms.
POINT 5, THE MOST CRUCIAL: When the Narrator actually sends you to Portal within The Stanley Parable, he claims he's sent you to a different game. But underneath the map, after falling down the elevator, it appears that the testing facility is among the maps and stages for The Stanley Parable as well. If you were sent to a different game, why would files and maps for the original game be mixed in with it? I REST MY CASE.

So, I just saw a youtuber play The Stanley Parable today (so now I want it) I've played some portal and watched my brother play the rest. This is quite interesting. Quite interesting indeed.

i have both games and they are awsome! and that's a very convincing theory...

Stanley Parable is made with Portal 2's engine...

PastaBaconNoodle: I am highly aware that they used Portal 2's engine, the question now is why, of all games did they choose Portal 2? With all the other points in mind, consider that.

Maybe for... atmosphere? xD I have an idea, but I can't word it.

Ooh, I forgot this one:
POINT 6: In the portrait you find in Portal 2 of Cave Johnson and Caroline, you can see a lot of bookcases. In TSP, there are a bunch of very similar-looking bookcases in the Boss's office. Of course, if this was at the time when GLaDOS had kil.led everyone, Cave Johnson would already have died. The portrait of the boss you see in the office (which hides his face for unknown reasons) is the next boss after Cave. That last part doesn't really prove anything though, this point is simply interesting for the bookcases.

Right, right, I remember now. I would guess because it seems simple enough to control the character (Stanley or Chell), and without jumping the game wouldn't break. So... controls?

And theyre both made by Valve (c), right?

^Not exactly, though Valve helped out.

This theory blew my mind.

It's well written, it's smart, and it's backed up by facts.
Except I haven't the slightest idea what The Stanley Parable is

Ya but before he goes into Portals he's in minecraft(I thought that was totallly awesome!)

Ehhh, Whatever. The game just crreeeps me out a bit. I've seen about 4 ending so far and i guess it awesome.

I'm not dissing your theroy

O.0 I never thought of that...

^I still have yet to read the comic, though if Doug was a scientist, they're probably at most simply related, since Stanley got the simple job to push buttons. Although, now that I think about it, the Narrator did once joke that Stanley only got the job because of family relations, so if they were brothers or something that would actually make a bit of sense. Not to mention Stanley's last name is never stated, so for all we know Stanley Rattman is a possibility.

I was going to make a Game Theory quote, but then I read the title.

I'm gonna guess that they did that so people like us make picture explaining THIS MADNESS.

^ I love how seriously you took this XoD
Just to make it all clear, these theories I make are never serious, guys. They simply point out similarities and coincidences that, when applied, sound pretty thought provoking. Oh, and yes, I understand. Everything you stated I already knew.

Though you are wrong about one thing, only the weighted storage cube wad used for the Portal ending, so all the other stuff like the companion cube are there because they used Portal 2's engine to make the game. :oP

BUT THAT'S JUST A THEOR- I mean... a very well thought out concept backed up with facts.

^I really wish there was a 'like comment' button...

But hey that's just a- I mean ,uh that's a very cool thought.

I've never played the Stanley Parable either but I heard it was fun :u I think you should become a theorist someday XD

*insert annoying Game Theory comment here*

I would read the theory, but I fear spoilers...

So... that means ol' Rover didn't find my comment annoying? :o

.....woah, that actually makes alot of sense! XD

Eight.

u may be right because stanley parable was a half life mod origionally. half life and portal series take place in the same time. perhaps stanley worked at black mesa instead. (black mesa is the company in half life against aperature.)

making a game therory quote because I found this

maybe stan forgot his kid then went home to take her there then well left her there and the following day glados dicided to change her vioce and follow stanly

@Hammerdstardust
This is interesting

@Soupibuddi

Hmmmmm yeah, Idk why I kinda thought similarly, they're both technically originally a part of the source program, Portal even shows up in The Stanley Parable, and they're both weirdly empty.