Much like film and television, video games utilize trailers to capture the feeling of the game in a short period of time. For a true video game fan, a play through trailer or presentation such as at E3 is by far superior, but to generate hype and to convey the feeling and emotion of the game, or even to just simply make the announcement of it existing, the trailer is required.
Hit the jump for all the bloody, fast and grunt-punting hype you can handle.