Aliens: Dark Descent Mission 6 - Nightmare and No One Can Hear You Scream Mode

Mission 6 Highlights:
0:27:05 - Clearing Hangar section
0:44:25 - 1st Onslaught
0:52:56 - Reaching Pressure Control Room
1:06:58 - 2nd Onslaught
1:15:40 - 1st Extraction (marine promotions)
1:17:34 - Days 20-22 Advancement (18-16 days left til bombardment)
1:29:48 - Stealthing my way to upgraded APC
1:41:12 - 2nd Extraction (no marine promotions)
1:41:47 - Day 23 Advancement (15 days left til bombardment)
1:48:05 - Deploying Main Bridge in processing center
1:50:50 - Terminal 1 defense
1:53:48 - Terminal 2 defense
1:59:00 - Entering Power Core section
2:00:09 - Terminal to deploy power core bridges
2:01:21 - Queen
2:11:30 - Final Mission 6 Extraction
2:13:25 - Days 24-26 Advancement (14-12 days left til bombardment)
I love this game. But there was/is a substantial learning curve. This playthrough is probably the most smooth and efficient playthrough I've had with this game. Probably the least amounts of death as well!
At this point, this is my FIFTH playthrough of this game. This playthrough is done on Nightmare difficulty and No One Can Hear You Scream mode, which limits saves to deployments from the Otago and creating a rest room to rest and save in. I also survive the game without losing any marines (thanks to some selective and well-timed reloads) and I get each class of marine to level 10 by Mission 10.
A few things to note:
I abuse the rest exploit regularly and even extensively in some parts. The rest exploit is where you rest and then reload the game and rest again. Majority of rest areas allow the exploit to be done and typically as much as you want. There are some random exceptions, but typically you shouldn't have any issues.
Suppressive fire, suppressive fire, suppressive fire. This will save your ass a lot! I wish I had known how much easier some of the encounters during my first playthrough would have been using this gameplay mechanic.
I tend backtrack in an effort to collect as much as I can, which can add a substantial amount of time to your playthrough. The missions generally provide you with enough supplies where you shouldn't have any significant issues. Tool and health kits may get a little tight during some of the missions, but you can always extract out and restock as needed.