User blog comment:Agent47JN/Hardest Mission/@comment-5219092-20130712005900

I'd probably say the Flooded District, but only because of the second half when you're trying to wind your way back into the Old Port District. The Weepers are obnoxious and the Tallboys in the section with the corpse disposal area have one heck of a range in the open area. I mean, they're not incredibly diffucult, if you reload saves a couple of times...

Also, for the Loyalists mission, it's pretty simple getting into the Hound Pits if you enter through the top floor. You just have to take out the three on the top, and then two on the second floor. After that, Piero's Blueprints should be pretty simple to get... Unless I messed up the guard patterns somehow. But either way, the Flooded District is certainly the most diffucult, for me at least.