That only works if you're a world renowned game studio making a highly anticipated sequel. Not when you're a relatively unknown indie studio making new and innovative games.
Though this would work wonders when Frictional becomes big (not if, when), they need to advertise as much as possible with things like they did today by releasing a video and MP3 to show people how truly terrifying and awesome this game will be.
If it was possible, we would do just that The way to play Amnesia is to start it up knowing nothing.
But then chances are high that only a dozen people would buy the game and we would have to look into doing something else.
One could do PR using stuff that where not part of the game, but then we would have to direct massive resources away from the game. This would make the game suffer.
what i meant was after release vids and maybe around 20 screens release nothing else. mgs2 was a good example because they relased a shit ton of info and a demo then had a period of 8 or 9 months without any new info