Subnautica

It'll be very hard to avoid getting this achievement for building a habitat to live in - as this will be pretty much essential to have to survive as you get further through the game.

First you need to craft the Habitat builder, using the Fabricator - for which you'll need a battery, a computer chip and a wiring kit.

You'll likely be doing this in the very early game where materials are scarce and its not yet clear where to find things. The wiring kit requires Silver - which is found in regular resource nodes but only commonly at depths of 60m-90m, so you'll need to dive down a bit to find some.

Then use the tool to construct a piece of habitat, plus a hatch - which will require some Titanium. Any piece of habitat that you can get into is fine, it doesn't have to be a full "Room"; e.g. the basic tubular hallway is good.

Build a Seamoth - this will likely be the first transportation you craft. The fragments you'll need to scan for this are around wrecks in the Grassy Plateaus area.

Note you will also need a Mobile Vehicle Platform to be able to build and deploy the Seamoth.

This is the building at the north end of the mountainuous island North of the Aurora crash site. You'll need a Purple Tablet to get in, but there are a few around in/on/under/inside the island. The achievement will unlock as you walk on deeper inside the building.

Find the habitat on the floating island, which is in the misty cloud behind the Aurora. There will be a waypoint to it (the "Aurora Rendezvous Point") as you progress through the story.

To unlock the achievement, as with the other Degasi habitat achievements, you need to pick up a specific PDA - in this case its the "Storm!" PDA inside the base in the lowest area.

Once the Aurora's drive core goes critical and explodes, you can (and should) go fix the mess. Kit up first: a Radiation Suit is non-negotiable, and bring a Repair Tool, a Laser Cutter for sealed doors, and ideally a Propulsion Cannon for rubble. Enter through the blasted-open bow section, work through the ship to the drive room, and weld every breach on the reactor - the achievement pops when the last one seals. The radiation zone then clears after a few in-game days, opening the wreck up for proper looting (Ordered the Prawn lives in here too).

The Cyclops needs nine fragment scans - three each of Hull, Bridge and Engine. The gentle route: a Mushroom Forest (the one northwest of the Aurora) covers hull and bridge parts, and the Crag Field or the Underwater Islands wreck covers engines; the east side of the Mountain Island has a bit of everything. Then build it at a Mobile Vehicle Bay floating over water deep enough to hold a 54-metre submarine.

Materials are a proper shopping list (plasteel, enameled glass, advanced wiring, lubricant), but the reward is your mobile home for the deep game - the Lost River chain (Follow the Lost River onward) is far more civilised with a Cyclops.

The jellyshroom caves are quite near where you start the game, down from the Safe Shallows. There's a base about 300m deep. Inside the base, find and use the PDAs within to unlock the achievement - the PDA you'll need is in the top part of the central area of the base.

The quickest Prawn Suit blueprint is inside the Aurora: the ship's vehicle bay holds two intact suits, and scanning both completes the blueprint between them (wreck fragments elsewhere also count if you'd rather not go in). You'll need the post-repair Aurora trip anyway (Extinction Event Avoided), so do both in one expedition.

Build it at the Mobile Vehicle Bay - the mech is your deep-biome workhorse, and with the depth modules it's how you'll walk the lava zones for Thermal Activity and Fourteen Thousand Leagues Under the Sea.

The third Degasi base sits in the Deep Grand Reef, roughly 500m down - follow the story waypoints (or the giant cove skylights south-west of the Grand Reef) and mind the resident Crabsquids on the approach. As with the other Degasi bases, the unlock comes from the PDAs: enter and hoover up the logs inside.

Whilst you're down there, pick up a Cuddlefish egg from the base floor for "Man's Best Friend" - saves a second trip to an unfriendly neighbourhood.

The Disease Research Facility is in the Lost River - the eerie green brine-river caverns beneath the map, entered most easily via the Blood Kelp Trench or Bulb Zone entrances. Follow the story waypoints through the northern arm past the giant skeleton and into the facility; walking in deep enough pops the achievement, and the story takes a turn.

Come prepared: a Cyclops or a well-modded Prawn/Seamoth (500m+), and don't taunt the River's ghostly residents. This is the doorway to the endgame chain - Thermal Activity and Fourteen Thousand Leagues Under the Sea lie beyond.

The Primary Containment Facility is the bottom of the world: the Lava Lakes, roughly 1,400m down, below even the Inactive Lava Zone. A max-depth Prawn (or very carefully driven Cyclops) gets you there; the facility's entrance wants a Blue Tablet - collected at the Thermal Plant (Thermal Activity) or crafted from its ion tech. The achievement pops inside, and what's waiting in the aquarium is the game's great reveal - the road to Optimal Health starts here.

The Alien Thermal Plant sits high on the wall of the Inactive Lava Zone, around 1,200m down - descend from the Lost River into the great lava chamber and hug the perimeter until you find the structure (the local Sea Dragon is the reason to hug the perimeter). Entry wants an Orange Tablet - one is cached along the Lost River route if you've been thorough. Inside: ion cube technology, the blue tablet for Fourteen Thousand Leagues Under the Sea, and a lot of lore. Achievement pops as you explore in.

Kit: Prawn Suit with depth module and grapple, or a shielded Cyclops parked somewhere unburning. Heat is the terrain here; plan your hops.

The cure comes from the Sea Emperor's children. In the Primary Containment Facility (Fourteen Thousand Leagues Under the Sea), the Emperor sets you the errand: gather the ingredients for the hatching enzymes (she points you to each - all obtainable in the nearby biomes), cook them at the facility's incubator console, and hatch her eggs. Swim with the hatchlings and collect the Enzyme 42 they shed - your infection clears, the achievement pops, and the gun on the Enforcement Platform will finally let you leave (Go Among the Stars).

The ending. Cured (Optimal Health) and with the gun disabled at the Enforcement Platform, build the Neptune: launch platform first, then gantry, boosters, fuel reserve and cockpit - a hefty materials bill including ion cubes and a Cyclops Shield Generator, with the blueprints handed out through the endgame story. Climb aboard, run the pre-flight, deploy your time capsule (Leave Only Time Capsules - genuinely don't forget), and launch. Credits, and one of the best endings in survival games.

Historical note: this achievement was glitched at launch in early 2018 and famously refused to pop; it was patched within weeks and unlocks reliably now.

During the Neptune's pre-launch sequence (Go Among the Stars), the cockpit interface offers a Time Capsule: choose a few items to bequeath, add a screenshot and a message, and deploy it before you hit launch. It pops on deployment - and your capsule genuinely enters the pool that other players find in their own worlds, so leave something kind. Miss it and launch anyway and the save is done, hence the missable flag: make the capsule part of your launch ritual.