There's an art to a good video game demo. How do you make a slice of a game available to prospective buyers that's both representative of the final product and small enough that they still want to buy it? A video game is interactive, so a perfect "trailer" for a game should also be interactive, but how do you ensure that you're not showing your whole hand? A movie trailer can include a curated slice of narrative, but a demo must include a curated slice of gameplay, just...