So I just had a fun solo attempt of the DLC on Nightmare (level 27 warrior, sword and shield, no specialization)
The first ogre at the start fell to its death. I wanted to quickly see how Immortal I could be with maximum tanking gear and for that I needed the mats and schematics, so I didn't bother trying to fight him.
After a quick death, the first two genlocks alpha were lured then skipped.
Burn the bodies: I first kited the spiders from earlier to the room with the Ogre. I then jumped down the cliff and survived, skipping an entire level. The door leading to the undead room was closed, so climbed my way with the lift back up (the door is closed until you kill all the darkspawns and burn the bodies). Once above, I tested various incoming damage. Turns out normal mobs (except emissaries and poison) only hit for one damage even without a shield. I then killed all the genlocks and tested the grab on the Ogre. Good news: the punches eventually stop. Bad news: each subsequent grab seems to be doing more damage. Or the damage is random. I don't know. He also can grab you in the middle of a charging bull. Which means you have half a second to dodge the grab. My reflexes are no longer what they used to, so I may or may not have had troubles here, but eventually he decided to jump off the ledge as well. Those darkspawns clearly need to see a therapist. I cleaned up the remaining mobs and burned the bodies.
Moving on, the undead pack. The same undead as usual, the archers deal poison damage. That was enough to make me skip the room. There is a cave with a lonely Genlock alpha. I said sod this game, if they're going to exploit bugs to ****** me off, I'm going to exploit AI too. This one died, swarmed by deepstalkers munching on him while he was desperately trying to kill me behind a pillar with his throwing axes. What a painful way to die. Back to the undead room. I quickly opened both doors (didn't remember which one was correct) and moved on to a few more 1 damage mob packs. Some spiders, archers, maybe an emissary? Who cares.
Finally, the Flaming room.
My first tactic was to kite the Shrieks to the Elite Corrupted Spider room. Turns out the room with the Ogre is closed at the start, and the Genlock Alphas are locked inside, who knew? So I have to kill 10 shrieks and 2 darkspawn alphas. I first killed the darkspawn alphas, and kite the massive amount of shrieks to the Ogre room. I was using +7.5% damage per enemy [scratch that, I forgot I actually switched that masterwork for a Heal over time when damaged]. But killing the alphas didn't open the door, so I had to finish my little tickling friends. The door finally opens, and the two Genlock Alphas are right there for the taking. No bridge, no nothing. I foolishly engage them AND the ogres, thinking, I don't know, that 15% more damage was worth it, or that I really should mutualize the Mark of the Rift casts, but am quickly reminded of my mistake. Back to the Bridge. Grinding focus. I end up killing the last two Shrieks by accident, you will be missed. I managed to exploit the Genlock Alpha AI and blocked one another on the edge of the bridge, until one fell down. Pfew! I could engage the last one and eat only the puny melee attacks rather than the devastating ranged attack. Down goes the second Genlock Alpha.
Time for the Ogres. I was sick of waiting. Cadash, meet Ogre Alpha #1 and #2. Thinking about it, it's probably possible to lure them out of the room and throw them downstairs, but I wanted to end this stupid 2h40 session. I had gathered all the info I needed. So I try to fight them the hard way. Eventually, I get grabbed during Charging Bull once, twice, on the third I fortunately have a regen pot up, but on the fourth time, down the guard goes from full, down my 1500hp go, and boom goes the Cadash.
Pfew. Tons of fun but veeeeeery slllllllllooooooowwwww progress. I have some ideas for the next attempt, but probably not tonight.
Edit: bonus image album (because it's fun)