http://www.chuckhawks.com/shooting_uphill.htm
The fact aside that its pretty much impossible to hit any of the targets, how far away was each target? edit: The girl kept screaming "X mil" and after some wiki research, isn't that information kinda useless for a target thats closing in on you at missle speed?
However its certainly not easier or more comfortable to precisely shoot +70° upwards than it is to shoot -20° downwards.
It's particularly hard if you have no time to adjust after you just shot 3 targets at horizon-level