Shipwrecked is located at Venus > Ember Caves and requires the player to be lvl 30 to enter, and the main ending rewards the player with the Worm Slayer (White heavy weapon with 390 base stat and 300% crit perk.
This guide will not go input-by-input like the others due to Shipwrecked's complexity and length, and will instead be more a guide on how to progress.
Firstly, please use this map created by Bhelogan (the creator of this story) as it will be used as a reference throughout this guide. --> [LINK] (shown above) (note that there is quicksand at 3N 5W, 4N 2W, 4N 4E and 1N 5E, stepping in quicksand without the 10' pole will instantly kill you)
The opening sequence is as follows: Disable the Bomb > Green Wire > Blue Wire > Cut the Red Wire > Power off the Engine > Run Alignment > Power the Engine On > Prepare for a crash landing!.
First thing you want to do after landing is to head to the Oasis (3N 2E) and fill up all 5 water skins.
Then you want to head to 4N 3E and then go North twice (to 6N 3E), collect a flower, and then South twice (be careful not to misclick otherwise you might run out of water and die, thus being forced to restart).
Return to the Oasis and fill all the water skins but one (this is very important for the upcoming language puzzle).
Head to the Settlement (1N 4W) and then Try to learn the Native Language
The language puzzle sequence is as follows: Hand Signals > Point at the Sky > What Next > Nouns > Me > Hand Signals > Point at the Sky > What Next > Nouns > You > What Next > Verbs > Drink > What Next > Hand Signals > Point towards your Flower > What Next > Verbs > Trade > What Next > Nouns > Water Skin > Great news Harukin!.
Now that you have access to the settlement, you'll want to Explore the Town
TO GET THE FIRST ENDING PRESS "SETTLE DOWN AND LIVE WITH THE NATIVES", OTHERWISE KEEP FOLLOWING THIS GUIDE TO GET THE OTHER ENDINGS
Go to the market and purchase the rope first and fill up your water skins
You will then want to climb the cliff at 0N 1E and follow the steps to open the chest and receive the shovel.
Then, you want to climb back down, head to the crash site (0N 0E/W) and dig to receive the 10' pole, which will allow you to survive quicksand.
You can then go to 1N 5E to dig up an infinite amount of water skins so you never have to worry about buying them (if you dig up enough to make your item count reach ~60 you should have more than enough to never worry about refilling them again after the first time, if not then refill them when mentioned).
TO COLLECT THE SECOND ENDING, HEAD TO 3N 3E, THEN GO EAST > EAST > NORTH > EAST > EAST > EAST AND THEN SETTLE DOWN IN THE HERMIT HUT (THIS HUT IS NECESSARY TO REACH THE OTHER 2 ENDINGS, BUT IF YOU WANT THE ENDING SPECIFICALLY FOR THE HERMIT HUT YOU CAN SKIP A FEW STEPS TO GET IT FASTER), IF YOU WANT THE REMAINING TWO ENDINGS, CONTINUE FOLLOWING THE GUIDE BELOW
You will then want to re-fill all your water skins, and then collect another flower, return to the village and purchase the Knife and torch (you'll need to do the trip 2 times since you can only carry a single flower at a time)
FOR THE POLE VAULTER ENDING YOU CAN SKIP GOING INTO THE CAVE AND FIGHTING THE BEAR AS MENTIONED BELOW TO SAVE TIME
Once you have all of those items, head to the cave entrance at 0N 2E, enter the cave, punch the bear first and then finish it with your knife. You will receive the Heavy Blaster upon doing so, but won't be able to use it yet.
Head to the Oasis, fill up all of your water skins, then head to 3N 3E
From there, go East > East > North and then East to 4N 8E, where you want to enter the Hermit Hut
Inside, you should first fill all of your water skins and then open the chest using the code 5 2 0 to receive the hatchet. You will then want to exit the hut and return to the Oasis to refill all of your water skins (be careful and avoid the quicksand at 4N 4E by going around it)
FOR THE POLE VAULTER ENDING, YOU HAVE TO DIG AT 2N 5W TO RECIEVE A SENSOR, FOR THE WORM SLAYER ENDING YOU CAN SKIP THIS
You will now want to head to 6N 5W and cut down trees with the hatchet, and combine this with your rope to make a raft.
Head to 6N 4W and then use the raft to cross to the other side.
FOR POLE VAULTER ENDING, YOU WANT TO VAULT OVER THE CRYSTALS AND THEN USE THE SENSOR, FOR THE WORM SLAYER ENDING CONTINUE FOLLOWING THE GUIDE BELOW
Once you cross the river, dig to collect the Crystal and fill up all your water skins
Then, return over the river and head to the Settlement
At the settlement, you will now be able to purchase a power core using the Crystal you found (make sure to also go back and pick up a flower so you can buy some more rope before continuing)
Head to 0N 2W and enter the cave, and then use the Heavy Blaster with the power core to kill the Worm.
From here on you are on a 'timer', so it is crucial to make sure you don't make any mistakes
You will now want to head: East > Down > South > South > Up
This should take you out of the cave, and then there will be some straight forward options to finish the story and receive the Worm Slayer ending (and the heavy weapon that comes with it)