So I am trying to get the Local Hero achievement, and realized one of the citizens was killed, so I let myself get killed and restarted the checkpoint. Mind you, I am playing on EASY, and before I let myself die, the robots were relatively easy to defeat, but now, since I reloaded there seem to be MANY more robots, and more often than not, they are not even taking damage when I shoot them. Needless to say, it is now impossible to save the citizens (any of them, really) and I tend to get killed anyhow without trying now. There does not seem to be a way to change difficulty while playing the game, but it certainly seems like it changed drastically for me. Makes the DLC unplayable after Act 1.
EDIT: Ok, I figured out why they are unkillable, but the difficulty has definitely changed to a much higher difficulty. Had ZERO problem dispatching them before I reloaded, and now it is nearly impossible. Definitely impossible to get the achievement though. My only recourse is to RESTART the whole game and pray I get the achievement before I have to reload, because this is DEFINITELY not the same difficulty I started with. No way to verify that, however, that I can tell.
Platform: XBox One