Well it works great, although most of the free ones don't look too good. The window I'm using is on the second story and several of the free ones would fade out a bit to give the illusion of depth. Unfortunately that means they don't have the sharp contrasts that make it stand out, so unless you're really looking at the window, you don't notice anything is there.
On the other hand, the giant eye and hallowindow itself look great. I think I'll mainly keep it on the giant eye, then switch it to play hallowindow if I see a bunch of people outside. Although, I'll make sure to make a video that plays the eye for 10 minutes, then hallowindow just in case theres constantly a lot of people and I can then just let it run.
*edit* just started burning the new dvd. It now has 4 options: just the eye, just hallowindow, 10 minutes of the eye followed by hallowindow, and 30 minutes of the eye followed by hallowindow. I figure that should cover all of my bases.