The Driftstone Fortress is a key plot area as well as a large area to explore which also contains pivotal materials. Due to its importance to the story and some key points about it, it deserves its own wiki page.
There are spoilers here. If this bothers you leave. Now. Seriously last chance.
The Driftstone fortress can be encountered one of two ways- finding it though exploration or through story plot. Upon going to meet the Merchant of Clouds, you will be captured, stripped of your gear, and dragged here. This is simultaneously a very bad situation and a VERY lucky one. MAKE SURE NO MATTER HOW YOU ENCOUNTER IT TO GET THE FIRESTONE INGOTS AND VULCAN STEEL. THESE ARE NEEDED FOR END GAME CRAFTING.
- IF you encounter it through exploration- take advantage, there are important items here if you wish to gain early access to some end game materials and ship building capacity. Namely Vulcan Steel and Firestone Ingots. Fair warning, while you most likely outgun the SOC here, they can come packing some heavy weapons and will not hesitate to riddle you with holes. Do not leave without the materials mentioned earlier, unless you want to be stuck in a terrible titanium(at best) ship the rest of the game. You have been warned.
- Story. Ah so you got yourself captured and locked up. Great! That's how its supposed to go. There are a couple of options for escape, even if it may not seem that way at first. First work to your strengths. Depending on your highest level stats (hopefully you've looked at the Stats page on this wiki) you can determine what means you rely on to escape. If you have nothing maxed out escape can be very difficult.
- High Strength/Vitality- Break down the door, and punch the first SOC you encounter to death. This is stupidly straightforward, but make sure to be jumpy about it. Bullets still kill you, even if you are superman. This works great if you have maxed out strength. Almost every SOC here will drop a gun and ammo, though not always. Loot the first chest you come to and get a weapon for sure. Now you can proceed as you normally would in any temple. The SOC here have very high drop rates of ammo and weapons, and in the upper left corner your gear is stored, behind a locked door.
- Anything other than THAT^. WELL, if you only have high Wisdom or Agility, unfortunately you kind of get the short end of the stick in here. The easiest way I have found, even though it is significantly risky, is to smash the bed, collect the cotton and make a rope. This can be used as a grappling hook, and you can swing and jump across the bottom of the structure until you reach a trapdoor to the right. Best bet is to enter here. OR you can swing across the bottom all the way to the left and back to your ship, and make weapons there from mats that you have stored on board. This is great for maxed wisdom builds as it gives you HUGE firepower advantages. Too stingy to waste mats on something like that? Me too. Agility builds are best off going in the trapdoor, and finding any box with a weapon in it. Then jump n' gun to victory. Your normal gear is in the upper left corner in a box behind a locked door.
"But I have all my stats maxed, which is the best way?" Bring or make a knife. Stab EVERYTHING. Seriously. Lots of drops to be had and breaking through walls and floors makes navigation SO MUCH EASIER. Just... try not to break through the bottom floor and fall to your death.
"But I'm not there yet, I'm just reading the wiki and can't resist spoilers/am trying to get ahead in the game, what should I do?" Prepare ahead of time. Stow all your crap on your ship prior to meeting the Merchant of Clouds. Then read Agility/Wisdom walkthrough and follow the high wisdom build, only instead of crafting crap, grab your normal gear. I also suggest maxing out a couple stats prior to getting caught.
Do not jump out the bottom of your cell, you will fall until you either hit something or choke. Once dead, the "go to town" button will be unusable, and you must load a save instead.