Look at you video at 3:10
http://www.youtube.com/watch?v=Jd3-eiid-Uw&feature=player_embedded
Here it happens that the one target in front would be outside of the screen, i mean the screen is to small to display the correct perspective. Suddenly the 3D-effect disappears, that's because the target is just shown half. Then the target disappears completely, the 3D-effect appears again because every target is completely shown again.
It's not wizardry in any sense.







