Yes, demolition Man is a difficult mission, it took me a couple of tries to get it. The key to passing it is being familiar with the controls, if you're using the PC version: W is climb up, S is drop down, 9 is go forward, and 6 is pull back, and 4 and 5 rotate/turn. Holding the 9 key will make uor helicopter go down slightly, so hold the W key down as well as you do that. Now as soon as you pick up a bomb, the timer starts, so get used to flying it, and get familiar with the controls before you pick up a bomb to start. When you do begin, you'll have to take the first bomb to the base floor, stay somewhat high when you go into the building, because construction guys will hack at your helicopter if you go too low. As long as your somewhat over the barrel marked with a purple blip, hit the CTRL key, and the bomb will drop, then rotate around and head back to pick up more. The next one will have to be placed on the floor above, and theres a central stairway in the middle use that, each bomb after that will have to be placed one floor up, Be carefull when you get to the 3rd floor, becuase a DBP security guy will shoot at you., but if you swoop down and ram him, he'll
go flying and probably die. Thats about all I can say for that my friend, hope it helped.