Pardon if someone else has already beat me to this, but after reading a few threads about how terribly brutal and unfair Survival Mode is, I have some strategies to share that seem to work. I'd love to hear more of them.

First thing I learned (well, after 5-6 dead vaults) is that the quickest way to have your shiny metal posterior region presented to you in a rather undignified fashion in Survival is to play it like vanilla. Just don't, because you can't. At best, you'll make it as far as about 20 dwellers and then get utterly destroyed by endless raiders.

Survival Mode is mean, and you have to get mean right back. Things that are working for me:

1. DON'T waste resources fighting lots of incidents. I was used to slugging it out with every fire and radroach attack. You can't do that in SM. Instead, choose your battles, make them few, and run like hell the rest of the time. Incidents come too fast and often in SM. You just can't keep up with them.

2. Exploit incident immunities to the fullest. Pregnant dwellers don't take incident damage. Neither do dwellers moving from one room to another, dwellers in Coffee Break mode, or the two dwellers stationed in the Vault Door room (except against raiders and DCs, but they're easy to dodge). In the early game, focus on securing about 4 males with decent CHRs and try to make the rest of your team female. Find CHR outfits when you can, and use them and the males to keep your females pregnant. That way, you only have to keep your males out of danger during incidents - the women will all run and hide.

3. Grow SLOW. Start with a single Living Quarters (8 dwellers), gradually upgrade twice (+2 each). If you don't have living space available, your female dwellers will remain perma-preggers and any new dweller candidates will stay outside the front door. When you open up new space, babies will automatically be born to fill it. Use the living space restraints as a growth control: the fastest way to die in SM is by growing too fast.

4. Be very, very conservative with your room building. Don't build rooms that you can't fully man right away. For your first three production rooms, stack a water, power and food vertically - putting power in the middle and stacking them that way will help prevent blackouts in critical areas. You'll need that, because otherwise you'll end up in a situation (usually when you jump from 12 to 20 living quarter space - see below) where low power production is killing your food or water. Let the living quarters go dark instead.

5. The second you get a decent gun (usually via a lunchbox), put one of your expendable males outside to explore and find more outfits and weapons. Level up your people at low population levels. Focus on production as much as possible. Pull your explorer back in before he gets permakilled.

6. Remember that when you collect an explorer back into the vault, they return in Coffee Break mode until you reassign them. That means they automatically run from any incident and don't take damage. An easy way to Coffee Break someone is to send them outside and collect them right back immediately.

7. Finally, and this is really important, remember that when incidents spread, they DON'T do it on diagonals and they don't return to rooms they've already hit. Raiders and DCs sweep from top to bottom. Other incidents start in one room and then spread to two up/down/left/right adjacents. Use those patterns to keep your people out of the way and let incidents burn themselves out.

This makes for a tedious early game, but it works, and things do pick up after the 20 dweller point. Just watch out when you jump from 12 to 20 dwellers (adding an 8-man living space to an existing 8+2+2). At this point you'll have a bunch of pregnants and they'll all give birth at once, leaving the new mommies without their immunities. Wait on this move until you've leveled and armed people a bit, and have secured some decent CHR outfits (Nightwear and Initiate robes, at least) and can re-preg them quickly. Even so, you'll likely end up with 2-3 deaths before you can restabilize things.

Anyone else find strategies that work for them in Survival?

Nah.. Survival is too easy.

1. Grow fast! Make lots of babies, and send new advlts out to the wasteland immediately, preferably on the known timer "click" to get stuff within 10 minutes. Collect precious items and let explorers stay outside if you don't have enough food/water or direct assignment in the vault. Distribute collected items/weapons among those working in the vault, rinse, repeat.

2. Build only simple three-unit rooms - do not upgrade anything to avoid overpowered radroaches and molerats.

3. Build three-unit non-upgraded power room right next to the entrance, with strong workers (adds to weapon damage) and best weapons to kill-off raiders. Five raiders against 6 power workers using 3-5 dmg rifles and 1-2 legendary weapon(s) from lunchboxes? Pfff, no big deal. Yep, early lunchboxes are very important - if you only got silly "500 caps" cards and no legendary weapons than it would be better to restart.

4. Check your vault on 15-minute intervals so all three-unit rooms will appear ready to harvest (yep, including that three-unit medbay).

5. Get to 20-30 dwellers quickly, hold until you get all dwellers equipped with proper resource-helping outfits and shotguns using short trips. Then go for 50-55 dwellers where you will have dwellers capable of staying overnight (preferably up to ~20 hours) and no deathclaws yet, re-equip with better weapons. Then start breeding and training 10E generation of dwellers and trash all early ones. After that it should go as normal mode, if I am guessing it right.