For the Challenge Accepted Achievement, load up playthrough 2 and get 1 Point Blank kill with the Shotgun. Use 360rev or Horizon to rehash and resign this save as Modio doesn't work. For the 4x 15 Point Location Achievements, just load the save on playthrough 1 and they will pop. For the 50 Point Location Achievement Fast Travel to Southern Shelf then go to Southern Shelf Bay. Explore this area fully then the Achivement for exploring all areas will pop. Also if you haven't got the achievement for Phaselocking 100 enemies, go and phaselock 1 enemy and it will pop. UPDATE: Use the Exploring Achievement save First, as the Challenge Accepted save will pop the 50 point Explore All Areas Achievement Out Of Order. Thanks to Fatpat666 for letting me know.