The Stanley Parable is a ridiculous metagame which is fundamentally a walking simulator/decision maker. Ironically, The Stanley Parable is a game about decisions, which makes it hyper-short, because to make decisions in a video game takes a lot of work, so the game can't be very long. It is a hilarious game, and was a lot of fun to experience. Ironically, for a game about not making any important decisions, you do throughout it.
So how did they demo it?
By making something which parodies the idea of a demo, which is strictly linear, gives you absolutely no choices at all, and which plays around with the player.
The demo is an enjoyable experience and, despite its own claims to the contrary, actually does a pretty good job of setting the player's expectations for what the actual game is like.
Try the demo before buying The Stanley Parable. If the dry humor of the demo amuses you, you'll probably like the real game.
Note that nothing in the demo is really in the main game, further lampshading demos that don't represent the game while simultaneously ironically representing it very well.
5.0