After the release of Patch 0.7, Nightmare mode is no longer that “impossible”. They have re-balanced the mobs in nightmare mode, ie lowered their levels closer to the player’s level.
However, I believe they left out a zone or 2 in this process. My Elite character is now level 39 going on level 40. Currently I’m at Monument Station doing the quests there. Thus far, all the way up to this point, the mobs have been challenging but you still had a fighting chance to beat them.
Now, I got a couple of quests over at Upper Grounds. When I entered the zone, I found the mobs strangely “resistant” to my attacks, and my bots died so much quicker than usual. So, I took a look at the level of the mobs, and they were level 47! That’s 8 levels higher than me!
Without a doubt, I died multiple times just trying to kill the named boss Lament. Eventually, after dying countless times, I cleared a small area where I could snipe at Lament from afar. Even so, it took over 10 to 15 shots from my sniper rifle to down him, not including a couple of nukes thrown in to help accelerate the process.
I don’t see how I can survive the zone to reach Waterman’s Walk, and even if I did, whether the mobs at Waterman’s Walk would be under level 47, or higher. If they are higher, or even level 47, I don’t see how I can complete the “Explore Waterman’s Walk” quest.
However, the other zones thus far in Monument station has reasonably challenging mobs. For example, mobs at Eastcheap are level 45, where they are challenging but not “highly resistant” to attacks.