That's pretty sweet.. I see what you're talking about when you say that screenshots aren't true 3-D images now. I thought about trying it but when I watched the video all the way through, I just use the same method I do with magic eye. You don't have to cross your eyes.. if you do the exact opposite (relax your eyes so they seperate and both eyes are looking straight forward but not fixated on one object) then you see the clear image in the middle and 2 fuzzy images on either side.
It works both ways, but if you cross your eyes for magic eye, you see inverted images. If you relax your eyes like I described above, you'll see the images come out at you instead.