I've already gotten all 5 of them in the last couple of days, but Well Done popped up the instant I finished Rapture and my time sucked. But medium was the easiest to get.

Is there a deadline for the medium rare achievement on steam or is it a permanant achievement?

Take the delay time off the -1 integer. Use only positive numbers for that part and make sure that time on/off are at the same interval, I've done this in my latest level City of Silence.

  I can't figure out how to make those platforms tha appear and disappear in the Rapture tile set? anyone know how?