I *might* have a run of this vid'd somewhere. I can't remember if I've already done this one or not, I think I have videos of all of Metropolis. But yeah, the key is the screen wrap. Duck until the top of the screen is right overhead. Then jump. The screen will wrap, and the brown doors become thin air while the screen wraps. It also would help to check out the maps here; figure out what path you're going to take to make sure you cover EVERY patch of ground.