Try not to rely just on rapidfire weapons.
I'm trying this with a primarily rapidfire build. That doesn't mean I'm going to use them exclusively, but I'm using a build centered on them because I believe they're powerful weapons, and I have already acheived (in the past) melee and even hybrid pistol build victories on N! (albeit before the anomaly existed). Using traits like SoaB, shotguns are *much* worse than rapidfire weapons in most situations, particularly taking out N! cacodemons in an open space (More on enclosed spaces later), but I still use them where appropriate, and for most of this crowded start-room ambush.
My strategy to get past the Anomaly is:
a) Get lucky with 2 phases and...
Of course. Not the 'tactic' I'm interested in here though.
If no phase devices, but I have a rocket launcher, I gather up what gear I want in the first room and drop what I can't fit right away by the righthand corners. I leave the globes be for later if I need them. I then equip red armor and the rocket launcher. I open the door, go out of the first room, and when the walls drop and I get raped, I rocket jump backward into my room MAKE SURE YOU DIDN'T CLOSE THE DOOR. I've found that with red armor on, and if you didn't hit any monster, just one rocket jump is needed to land you safely behind the door. Close the door and recuperate. From there, open the door repeatedly and pick off enemies with a mix of shotgun/rapidfire weapons.
First of all, I feel it worth mentioning this is pretty much exactly what I do on lower difficulties to close the anomaly. Hearing that you use it on N! I find *extremely* interesting. I'm unsure what I'm doing wrong, but 2 huge issues hit me when I try this (It was pretty much my default tactic when I had no phase devices but a rocket launcher)...
1 The first is that, after reaching the start room, I'm unable to close the door. Between nightmare demons catching me up, and nightmare Cacos knocking me aside, the door is always blocked by a N! demon. (interesting thought just now - 2 steps to the left, before the rocket jump, so that I'm in the right place to close the door, assuming N! cacos haven't hit me yet (doubtful, I guess)...) Not that I usually mind being in front of a blocked doorway, because I intend to knockback-trap them with a shotgun, and the AOE of a blocked up demon-swarmed door seems ideal. Leading me to:
2. No matter how well i use combinations of running mode, shotgun shell boxes for knockback traps, and medkits (bear in mind technicians use medkits in something like 0.2s) I *still* get slaughtered by the demon swarm. I assume my shotgun fails to knock back the rear demons, meaning the ones biting me have no squares behind them to go back into, so instead stay where they are and keep biting me. Also, N! cacodemons are just untouchable with a shotgun in this kind of build (obviously best to change to chaingun after the demons are dead, but resurrecting demons (due to the shotgun use causing an inability to kill them in doorways for no-corpse kills) soon ruin that tactic.) Attempting to fight the swarm of demons and Cacos with a tactical assortment of weapons and items is pretty much how I always die on the level, which had me convinced (before your post) that the only way through it was to skip it or berserk it.
Once that room is clean, recuperate, take inventory, change armors/whatever, and then advance to the bruisers.
You must be killing those demons SO much quicker that I can. I lose pretty much (ie completely torn apart) all my armour (including a 200% power-modded red last attempt), along with both large health globes, during the fight at the doorway! :D
Just to help me understand this, 2 other questions:
1. What kind of % success rate do you get with your 'no phase device' tactic? Because I've had some remarkably well equipped non-melee marines attempt it, and not a single one has managed to clear it.
2. You posted what you do when you are lucky with phase devices, and what you do when you don't have them. Would you mind going over what you do when you are UN-lucky with phase devices, given that it stops you from rocket jumping to the start room so quickly, and can even (often) land you deeper in the ambush that you were before...
3. What do you do when you have no rocket launcher and no phase device?
Good luck!
Haha, the day I have even mediocre luck on the anomaly will be the day I get my win, i think!
To note, I can make it to the anomaly about 95% of the time now, though, so at least I have training against the little ones, and I'm pretty confident that the new nightmare (not really new any more) will get easier when I can manage corpses more effectively using a rocket launcher. Thiis is my silver lining, don't take it away from me! :D