I feel bad for asking this since the quality of that demo was quite high but old habits die hard and I must know how long this experience is. This honestly would just determine if I am buying the game right now or during a sale.

There is an achievment to finish the game in 4 minutes and 22 seconds. You can play this game for hours and don't discover everything

It's hard to say as an answer could spoil what the game is but I have been playing it for 3 hours so far. I am not completely sure that I've seen everything yet.

http://www.howlongtobeat.com/game.php?id=14083

Been playing a couple of hours and I have no idea have much I've seen so far. So many diverging paths to go down,

sounds good to me, thanks.

So god damn many endings... I played for 2 hours and I think I've probably got most of them. There is some crazy shit in this game. Definitely worth 10 bucks.

If you feel unsure I'd watch this very spoiler light video:

i have been playing for 2 hours and I think I got all of them... i have taken all the branches I remember seeing but there is no way to be sure... Some of them actually made me feel something... ie(no spoilers, I give a vague vague name to the path and you would know what I am talking about only if you saw it, but blocked anyway) the path with the light show. The game feedback path was awesome.

Real spoiler here about the last two buttons on the main path: when you press "on", were you able to stop the countdown, i felt like it was possible but i didnt exactly get it, i only attempted once though.

I know what you mean about those two paths. Especially the light show one was pretty touching and the video game one went just into riddiculous lenghts to make it's point. It was incredible. I think the whole point of the countdown ending is that you can't stop it. It's the narrators fuck you to the player, so to speak. You know, it's a video game you are the player ie hero and there is million buttons and obviously you just have to solve the puzzle to win... but you can't win; not in The Stanley Parable. In retrospect we probably should have had this conversation in here.