So I have been playing ALOT of Bioshock: Infinite...I have 3 achievements left and I am currently working on "On the Fly" before tackling 1999 mode. I am having an issue with this one though. I have on the sky-rails moving around and shooting enemies (unarmored mind you) and the kills are not counting. Is there something else I have to do or is it a glitched achievement? I've looked up videos and they aren't showing me anything different. If anyone can help I would really appreciate it.