Brothers Colin and Connor McGuire wanted a Left 4 Dead movie... so they made one.
The home project took them the better part of two years, including 3000 hours of editing. The final product is about the length of an "hour" long television show, clocking in around 40 minutes, and looks at least as good as several TV shows I've seen.
You can find out more about the making-of from the video listing and the McGuires' Facebook page.