well it IS for the "Challenge Accepted" as well.
But the compl33tionist lvl5 is a pain in the ass to do, if you fail some of the objectives, only thing I can sugest to make it possible is to save and backup your savegame before you try on those missions, specialy in playthrough 2
If you fail a mission, quit the game and restore the save files you backed up.
[Edited by thebigschwag, 1/10/2013 3:39:08 PM]
Just use CoSMOS, change the number to 99 and do one more side mission. I completed most of the challenges this way, I hate grinding in most games, it just takes the fun out of them.