Calcutating in sharp, unclear positions

This is a game Kamsky-Gelfrand played just a few days ago. White to move. To find the right continuation, actually the only continuation 1.Qd6+ for me, 2050 fide rated player, in similar position takes unpleasant, heavy, energy-draining mental effort and long time. I wonder why. Is it because there is something I don`t know about calculation in unclear, complicated positions? Try for your self with an engine. 1.Qd6+ Kg7/Kg8 and see what moves you would have to find!!! It`s total madness. One sacrifice after another. But it`s not sacrifice that is hard to find it`s the point of it. Give such position to any U2300 or even to a 2400 I am sure none would survive it as White.

http://www.chessgames.com/perl/chessgame?gid=1622504

Well, White actually played 1.Qc5+, not Qd6+...

and I'm not sure that this sequence is hard to spot.