I have completed the game 100%, finished all the challenges and this acheivement did not pop. My says 100% overall complete so it is not stuck at 99% like ive read has happend to some people. Before anybody asks, yes I did do the challenge at Cliffside Bunker. I have gone through every area on my map and it is all finished. I am looking for any suggestions as to getting it to pop short of another playthrough as I dont think my brain could take it at the moment.