This is the tough bit, the bosses tend to stay back from the ledge yet continue to throw pinpoint molotovs at you from above, I stayed underneath and slowly snook out on the left keeping a watch upstairs, you eventually see one of thems head, shoot with a pistol for headshot kill. Reload and go back halfway (still not exposing yourself to the upper section) and two waves of 2 gun enemys run down the stairs, position urself to kill them before them get down.ДЎ more enemy appeared also on my go which noones mentioned (making 5 people that come from upstairs) again kill as you did previous. Run towards the back but sticking to the left.ДЄs you underneath the top section of the warehouse (to be safe from fire attacks from steve and derek above) you see some large girders, positon yourself behind them and kill the 2 gun enemys that spawn at the back of the warehouse This was the most annoying and frustrating part of the game for sure.Дriving the car to the back of the warehouse if rubbish as the 2 gun enemys kill you before you can get out of the car.Д«est tactic i found (cleared game now on hard) That leaves 1 guy left who you can kill from the stairs or ground. If you have the single shot rifle you can graze his head for an easy kill. If you set your cover up right the fire can't hit you and you can BARELY see steves head over a crate he throws the molotovs from. There is a roof beam and some crates (near the stairs going up). I triggered another set of 2 enemies doing the same thing so that left me with steve and 1 other enemy that do not come down the stairs.ДЄt this point I made a mad dash for the cover right near where you entered. When they come, run back to where you took cover earlier and take those 2 enemies out.

You will probably move just beyond the 2nd floor walkway to trigger them. Then I moved out on the left side (these directions are based on facing towards where you entered the building) to try and trigger a 2nd set of 2 enemies that come down the stairs on your right. Kill those 2 and take a rest behind the crates and reload whatever weapon your using. While your running towards the back you will have 2 enemies, one in front of you towards your right slightly and one basically directly to your right once your under the 2nd level.

I ran straight in and towards the back left (you will be under the 2nd level so you can't get hit with anything from the 2nd level, fire, guns, etc).

I died probably 20 times before I figured out a decent method. Your right about it being the hardest mission in the game. This is probably the hardest mission in my opinion, you have to be on your toes.

Mafia 2 stairway to heaven