Tried doing a projection of upward flying ghosts onto a large screen of vis-queen last year; didn't work so well. Biggest problem was that the neighbors figured they needed their 200 watt porch lights blazing at all times, backlighting my screen and making it completely visible. That, and the wind blowing it around caused trouble.
I may just tiptoe over and unscrew the things this year.
As for the video: it looked like a single projector from the front, because of all of the activity going all over the place. But it must have been a very BRIGHT projector to cover that kind of surface area.