So I tried it at last with my friend and we had some fun with it. ^_^ But noticed several issues also. First of all sometimes after changing controls menu freezes for some reason. At the same time it definitely works cause we hear some sounds. Another thing - in case if we press shift the game slows down. Pressing shift again put it all back.
P.S. It would be exciting to see from you some coop game with helicopters like Hornet Virus or Night of the little birds (not necessary with two helicopters, probably two players controlling one copter).