The demo is 20% of the game, and if you play it paying attention to everything it's around 8 hours, rushing it's 6 hours, if you play on both difficulties just *2+1 hour. Reason it's short, is because you don't die, a normal fps probably adds 3-4 hours in replaying time because of deaths. Even still, the game is worth it, and don't buy the collecters edition, I heard that a lot of the boxes have busted discs. Edit: Haha, another funny with the spider spawns