The second time on girders, you know how some people wait for the barrel and jump it, or wait until it almost hits them in the back and then jump and you get 100 points for proximity?
Well, what about the first blue barrel? I doubt it's original, but I don't recall seeing anyone doing it or talking about it, and so I tried it. It's not easy, actually. There's a special timing required, where you go behind the oil furnace, and right when the barrel hits the girder just above you, you run and jump, and clear it!
It has to be right, cos obviously due to how the game handles collision detection in that part of the screen, you don't even have to touch the barrel to die.
Try it out.