The Long Dark

Edit: Adding more tips after finishing this. Yeah, my ratio is going to take a hit. Please don't downvote.

Edit #2: As of the June 2018 update, there is now a signal fire in the new Hushed River Valley region. Next to the fire is a Moose backpack that increases your carry capacity from 66 lbs to 77 lbs. I'm sure I don't need to tell you how important that is.

Edit #3: There is a Custom difficulty that I haven't mentioned. You can turn off blizzards, and cause animals to leave you alone. This makes everything super easy, not just for this achievement.

Turns out this is really super easy, just long. You obviously need to prepare. I would suggest leaving this method for the end once you've explored and such.

1) Firstly, one big hint is that you need to keep your hatchet in good shape. I found myself worried at the end that I would run out of firewood. You can obviously wander out, but I wanted to hunker down to finish this. After I hit 500 days, and ventured out, it's not so much of an issue, but if you're hunkering for this, make sure you keep your hatchet handy. Limbs do regenerate. (One time I cut a limb and found two more show up behind me.)

2) Do this on Pilgrim. I didn't want to run the risk of investing 50 hours to lose it in a bear attack at the end. Animals don't attack unprovoked on Pilgrim. Your call. Things may be the same on harder difficulties. Food also spoils much less/day than other difficulties.

3) You should have warm clothing, but you're not going to need it too much here. Leave the majority of weight for food and water.

4) I suggest doing this on Coastal Highway. If you are scaling the mountain on this run, do it first. There are two spots you want to focus on: the Quonset Garage and the fishing hut closest to the Garage (which has a door). You're going to want to run back and forth between these. As stated in the comments, a garage/house is safer, uses less wood than a fishing hut, and has a bed so you don't wear out your bedroll. You will need to stay warm: the garage NEVER gets cold. You will need more wood at the hut.

5) You can use any hut you like, but I strongly suggest the one with the door (see the video below). The door cuts off the wind, although you will still have to deal with extreme cold if you stay there for a while. You'll want to save your wood for melting and boiling water at the stove in the hut.

Edit: A later update removed the door. Garage might be better.

6) Never have to light a fire outside. You shouldn't have to. Get to the Garage or a hut at all times. Those won't go out in wind.

7) Whenever you build a fire, BOIL WATER. Don't waste any wood on a fire just for warmth. You're obviously going to need water anyway.

8) For food: fish, fish, fish. Easy pickings. Take a lot of fishing tackles and as much wood as you can carry out to one of them. Hooks can be made with scrap metal; fishing line can be made with cured guts.

9) Immediately cook the fish when you feel like you have enough. Larger fish have great kcal/weight ratio. Cooked fish weigh less, increasing the kcal/kg. Salmon (which is only found at Coastal Highway) is better than most other fish, 455 kcal/kg. (Smallmouth bass can be found elsewhere, and is just as good.)

10) Cooked fish also last longer. On Pilgrim, a cooked fish kept outside decays 0.3125%/day. (320 days for a full decay.) Raw fish decays 0.8333%/day, so COOK YOUR FISH. (By comparison, cooked fish on Stalker decays 1.250%/day, and on Interloper decays 2.500%/day. Difficulty changes things a lot.) Remember, this for outdoor fish. When you go inside, leave the fish outside. While you fish you are outside, so it decays slower.

11) There are a lot of limbs lying around on shore and the islands, and you can raid a house for more wood.

12) Keep your clothes in good shape. Make sure you have a couple of sewing kits, and grab cloth from the curtains in the houses. If you run out of sewing kits, you can use fishing tackles. I've never had to do that.

13) When going to the fishing huts, don't forget the hunting rifle. There is a bear nearby. That means a LOT of very high calorie food. It can last you for many, many days. Cooked bear meat is the best in the game... but you have to kill the bear. It decays 0.20825%/day, and lasts 480 days. Yep, fully fresh cooked bear meat will last through your whole run, but you'll eat it before then. It's also high calorie: 900 kcal/day. Twice as dense as fish.

14) When hunting bears, take off your clothes. (You can leave them in inventory.) Keep bandages and antiseptic/lichen wraps with you. If the bear gets you, your clothes will be ruined. You can take the clothes off for a little without freezing, for the most part. I also suggest throwing your bedroll down and sleeping an hour first. Wildlife will stay in place, and you just created a save point. Now if you're caught, force quit the game and reload it.

Bears will charge on any difficulty, even Pilgrim. Note that the bear tried to get me, but couldn't because I was in the fishing hut. The bear then started to walk away. Here's the next part:



Seriously wounding a bear will make it crazily run away. You don't need to chase it. Wait about a day, and the bear will be dead. (Yep, the bear will die on its own.) The normal place that wounded but not dead bears will collapse is usually to the left of the view of this video, near the shore. This bear gave me 35 kg (78 lbs) of meat. Your mileage may vary.



13) Now. The main tip that will get you through 500 days, for those of you that actually read down this far.

Hibernation.

You can make it through a day with about 450 calories/day on Pilgrim. (Major thanks to SNAKBYT for your post in the comments.) Do this in warm place, like the Quonset Garage.
Make sure you have plenty of water. Keep the bulk of your excess food outside.

-Start at full warmth, full water, full fatigue.
-Skip 12 hours.
-Drink water (until full).
-Skip 12 hours. Your condition will fall. It's okay.
-Drink water.
-Eat around 300-450 calories.
-Sleep 12 hours. Your condition will improve. You will probably be very hungry. It's okay.
-Drink water.
-Repeat (skip 12 hours...)

This will be boring. Very boring. Boil water when you need to. When you are getting low on all your food, go fishing. Then repeat. It took me several days to get there, but I took breaks.

Hope this helps!

Too add to previous post if your going somewhere new because of boredom or whatever play the game offline so if u die u can clear the local save and resync previous save. Nothing would suck like dying on day 495......