The author of The Stanley Parable says that “it’s actually best if you don’t know anything about it before you play it.” And that’s probably true. So if you like, you can play it before continuing.
While we’re waiting, a bit of background: The Stanley Parable is a game by Davey Wreden made in the Source Engine. It requires some form of the Source 2007 engine to play, which you have if you own Half-Life 2.
The Stanley Parable, for all its exploration of interactivity and choice and video games, isn’t actually interactive at all when you get right down to it. Yes, it has six endings and branching and all that. But as with many games with multiple endings, as soon as you tell the player that they exist, she wants to view them all. And especially with Stanley‘s left-or-right, red-or-blue choice structure, trying out the choices exhaustively is trivial.
This isn’t a negative criticism. Stanley‘s forking narrative and multiple endings are a clever and affecting way to explore its themes of self-determination and conformity. (As an aside: artsy games tend to be about interactivity in the way poems tend to be about inspiration. This will never go away, no matter how much we wish it to do so.) However, because the game practically begs you to play again and again, the player is left with the impression of the game as a whole, not any one playthrough.
Imagine two ways of looking at a walk through a maze. The first is singular and reductionist: you saw a path, you turned left at an intersection, you saw the exit ahead. This is a first-person, linear, sequential view. The second approach is general and holistic: a view of the maze from above, with your path drawn in red. This is a third-person, spatial, synchronous view. The more you play The Stanley Parable, the more you think of it from above. You see the red path and the blue path simultaneously, as a game designer would, instead of as the PC would.
There are “non-linear” games which avoid this phenomenon. Think of the original Fallout, which provides enough choices and variable approaches that one can’t help but think of one’s own story. Or of “Balloon Diaspora,” which presents choices that don’t map nicely into a neat little tree. For that matter, tabletop roleplaying games tend to be so open to player choice that it’s literally impossible to predict the unwalked paths.
But in The Stanley Parable, exploring all the paths leads to nearly the same experience as every other player. You played through the game six (or five or seven) times, and got roughly the same set of endings. Maybe your endings happened in a different order, but it’s unlikely that you did anything particularly different than another player. Stanley seems aware of this, of course. As one of the endings states, the only real choice you have is whether to keep playing and let yourself be crushed by inevitability, or hit the ESC key and quit the game altogether.