The game has 40 achievements. 5 Achievements are story related but you would get much more just for finishing the game regularly without caring much about achievements.

Required playthrough: 1, but as the game is very hard dont think anyone could be ok on extreme difficulty without spending talent points so make it 1,5.

Make everyone happy: Make sure to make everyone happy. Avoid quest endings which hit any faction reputations hardly and balance out your quests so at the end of the game will be all friendly at least.

DONT kill anyone: While there is an achievement for having very bad karma it may affect companion quests, faction quests and might lock you out from earning some achievements. Some quests require you to kill the target, but try to minimalize the kills.

Dont waste 3 talent points for the same talent: You have 6 talents, like lockpicking, crafting etc. Dont max them out to level 3!, only once for the achievement, but save before and reload. Companions and few items increase these talents so getting any of it to lvl 3 is a waste.

Care about your companions: Companion achievements are easily missed, you need to finish all of their quests, build up reputation with them for 3 romance achievements. Also, dont forget to keep upgrading your companions with items, game is very hard, you need them!

It's a secret
This awarded for completing the Prologue.


Treason
This awarded for completing Chapter 1.


On the Run
This awarded for completing Chapter 2.


The Fall
This awarded for completing Chapter 3.


Hello, Earth?
This awarded for completing Chapter 4.

I must say i not perfected the game, normal already very challenging, however 38/40 is doable on normal in 1 playthrough easily, thats what i did. I missing the hard and extreme walkthrough, however finishing game in extreme unlocks all 3 achievements.

No achievement for finishing the game on easy.


Traveler:
It's for the normal difficulty.


Though to beat:
It's for the hard difficulty.


Extreme survivor:
It's for the extreme difficulty.

Loot chests, pick locks, skin monsters (exploration lvl 1 skill required, but if you equip starter head item then you get it for level 1 as its the bonus of that head item).


Monster Hunter
Kill 60 monsters, unlikely you will get far in the game before earning this


Lightweight, Middleweight, Heavyweight
Knock out 50/100/200 humanoids. Unmissable, you should have all 3 before end of chapter 1 or early in chapter 2.

Raider
Ransack 40 chests. Should be earned in chapter 1 already when you exploring and loot the chests!

Burglar
Pick 50 locks. Takes a bit longer but should be earned already during chapter 2.


Trapper
Skin 100 creatures. You can skin only monsters and you need to have lvl 1 exploration for it. You should have this achievement during chapter 2 if playing regularly.

Like lightning
Electrocute enemies 200 times. Just use your technomancer lightning regularly in combat and dont forget to add lightning effect to your weapon. (actually you select it for your character in prologue then it last for all combat types, for all weapons). You should get it already in chapter 1, perhaps chapter 2.

Ace of staves
Hit enemies 200 times using a staff. Select stave combat style then fight with it, could be earned very fast.

Sharpshooter
Hit enemies 200 times using a pistol. Select rogue combat style and use your pistol (left-ctrl). You can use it 4 times then its need cool down, still. Also hard to miss and easy to get.

Without fail. Parry 200 attacks with the shield. Select guardian combat style and keep blocking with left-ctrl. When fighting easier enemy groups just take a position and keep left-ctrl pushed, not takes much time.

well, well. combat talents. If you playing on extreme you cant really afford to not spend your talent points. This is why i mentioned that 1.5 playthroughs required if you go to completion. After extreme difficulty just rush to lvl 25 wihtout spending talent points on easy difficulty.

If you think the 2 hardest difficulty way too hard for you (like for me) and you ok with only 38/40 then you can go on normal, spend first 12 to be ok on battles, then save the next 24. If you finish sitequests, explore you will be likely to get to lvl 37 for that 36 talent points.

And why 24? Each tree requires 24 skill points to max out. The solution is to save every point until you have 24 skill points then save your game, max out one tree and then reload.

Guardian
Unlock the entire guardian skill tree. 24 talent points required.

Rogue
Unlock the entire rogue skill tree. 24 talent points required.

Technomancer
Unlock the entire technomancer skill tree. 24 talent points required.

Warrior
Unlock the entire warrior skill tree. 24 talent points required.

You have to start somewhere
Upgrade a skill. This will be the first achievement you earn in the game.


Expert
Unlock the 3 levels of a talent. Its the lockpicking, science etc, talent trees. Unlock one to max lvl, which is 3. Save before and then reload as pointless to have one on lvl 3 as you get bonuses from items and active followers.

DIY Freak
Make 100 equipment upgrades. At crafting station upgrade 100 items. Its actually missable, but if you playing on hard+ difficulties you need upgrade a lot, also follower items to make you and them stronger. you can also recycle items to get materials and you can just do lvl 1 upgrades on items.

At chapter 3 you will have a mission to get the support of 3 factions against Victor. The mutants will be one automatically, you need to talk with the leaders of other factions to get their support. If you finished quests in a mixed way, so one for X faction, one for Y faction and not favoured always the same ones and avoided quest endings where you had huge reputation hits then you should have all on friendly at least.

Save before talking to a leader and reload after, so you can go to all factions and get all these achievements in a single playthrough. Technomancer support doesnt give any achievements, also some support lock out other one so cant be paired, like only Vory will join if you asked the support of the Army, Technomancers wont join if you asked the support of the rebels. If you have friendly reputation to all just go to them with only the automatic mutant support so they will join and you will get that achievement.

Noctis merchants
Ally with the Noctis merchants. Leader is Dandoloo in Noctis, inside the palace.



Opponents of the regime
Ally with the opposition in Ophir. I think you need be careful in chapter 1 to not arrest/kill Bulgakov, the leader of the opposition during the quest which is about to protect the train from a bombing attempt. Bulgakov will be later and during the alliance quest in the Curiousity bar, in zone Slums.

The Godfather
Ally with the Vory. There are lot of possible reputation loss with Vory, so be careful. Vory boss located in the slums.

With my captain
Ally with the Ophir army.


Champion!
Complete the arena championship at the Curiosity's. Visit the arena in each of the first 3 chapters and clear out. Achievement earned after you clear it out completly for the third time in chapter 3.

Obliging
Finish 20 secondary quests. Just finish sidequests.


Bad Karma
Having bad Karma. I suggest to go for it after mid chapter 3 once done with all companion quests and romance options. You can get to enough bad karma pretty fast. Once you hit the required karma for the achievements your companions will comment about it, your actual lover will abandon relationship and you will have reputation loss with all your companion.

Save before using console (contacting Earth) in chapter 4, after Leviathan boss fight. Go for one ending, then reload and select the other one and repeat.

Martian forever...
Decide to join Mutant Valley. One of the ending......

Grand Master of the secret
Decide to return to Abundance. One of the ending......

Goodbye paradise
Decide to join Noctis. One of the ending......

These achievements are probably the easiest to miss, ill start with the all companion quest achievement as those required for the romance options anyway.

Best friend
Finish all of the companion quests.

You have 5+1 follower in the game, one available only in chapter 1. All companions have 1 specific companion related quests in each of the first 3 chapters. You need the companions to be in your party and then talk to get the quests unless in chapter 1 (with the exception of Jeffrey and Scott whose need to be in party for quest even in chapter 1). You also cant start another companion quest when you is on one.

Jeffrey

The feeling of being followed - Chapter One

Jeffrey is available only in chapter 1, and you actually will fight him at the end of the chapter. This one is very easy to miss. After completing both "The Deserters" & "Break the Opposition" (you will stop a train from being blown up) just talk to Jeffrey. He mentions the feeling of being spied on and will ask you to go along with his plan. DO SO. Before leaving the barracks to lure the spy, save the game because you can fail this quest.

Scott Seeker

A Professor's Worries - Chapter One

Once in the Slums of Ophir and with Scott in the party, speak to him. Ask if he wants your help to find what he's looking for to start this quest.

Scott Has Disappeared - Chapter Two

After the quest "In Search of The Lost Dome" Scott will vanish, talk to Dandolo about it. If you kill all of the ASC spies during Under Threat before speaking to Dandolo, he will disappear from his palace and the quest will fail.

Confession - Chapter Three

You will receive this quest instantly once you arrive in Mutant Valley, but first you need to get access to the city to be able to deal with this quest.

Lucky (Andrew Mancer)

Marks of The Past - Chapter One

Once completed "Merchant Rumours" there is a one armed guy close to the merchant for the quest. Once directed Master Connor to lucky spy out the conversation. Save vefore attempting in case you fail.

A Friend Found - Chapter Two

Midway of the chapter speak to Andrew about his feelings and about his lost arms. NEVER laugh on him.

Brothers in Arms - Chapter Three

Talk to Andrew in chapter 3 after entered the mutant city. He will mention that he will become a technomancer. Agree to it and do the quest to promote Andrew.

Amelia Reacher

The Explorer's Father - Chapter One

Once returned from the quest during "Counterattack", speak to Amelia in her Rover shed to obtain this quest.

Scott's Son - Chapter Two

Once done with "Back on Track" quest and repaired the rover speak with Amelia to get this quest.

In Search of Her Father - Chapter Three

In chapter 3 speak with Amelia to get this quest. Take Andrew as 2nd follower for the charisma talent boost as you will need it. Do the quest with preferaly with tier2 charisma skill+Andrew. Give the tablet to Amelia what you find near the rover of her father and dont allow her to kill Scott. Save before, in case you fail, but with tier3 charisma you have 100% chance.

Niesha

A Friend Under Pressure - Chapter One

Once you escorted the VIPs from Amelia's Rover Shed to safety (make sure everyone survived in that quest btw) talk to Niesha to get this quest in the Exchange.

Accountable - Chapter Two

After arrived to Noctis speak with Dandolo first, then with Niesha. Dont let her to kill the thugs during this quest.

Gloria - Chapter Three

Shortest quest ever, just talk to Niesha to pick it up, travel with her to Noctis, go to the marked location and donw.

Beg(Phobos)

A Body For a Merchant - Chapter One

This quest is received from Fiorello after the quest Memory problem side quest which can be started right after finishing a main quest with him.

Souvenir For a Mother - Chapter One

After completing previous quest speak with Beg next to Fiorello, the merchant. Just deliver an item to Slums and return to Beg for a talk.

Weapons For The Mutant Nation - Chapter Two

You can get this quest from Phobos (formerly known as Beg) after repairing the rover (back on track main quest).

Feuding Brothers - Chapter Three

You can get this quest from Phobos after completing quest: "A Guide For a Young Nation".

Once all done you will get the achievement

Soulmate
Enter into a romance with Andrew

Chapter one:

-finish companion quest
-eavesdrop on the conversation without being seen

Chapter two:

-once in Noctis compliment on his Charm
-dont laugh on him, never, not choise any dialogue options like that
-complete companion quest

Chapter Three:

-complete companion quest
-SAVE game
-speak with him again, agree to meet him in your room in mutant valley. Agree to sleep with him.
-LOAD to go for another romance achievement

The Spy who loved me
Enter into a romance with Niesha

Chapter one:

-complete her side quest "A friend under pressure"
-speak to Niesha after side quest and compliment on her career, then ask her about her life

Chapter two:

-complete companion quest and DONT let her to kill the thugs
-after the quest compliment her on her tenaciousness

Chapter three

-completed her companion quest
-SAVE game
-speak with her again, agree to meet her in your room in mutant valley. Agree to sleep with her and confess your love.
-LOAD to go for another romance achievement

A clockwork heart
Enter into a romance with Amelia

Chapter one:

-during quest "counterattack" when in the rover and heading to the mission site answer "you feel excited"
-complete companion quest
-compliment on her career after companion quest
-apologise here after escaping Abundance/Ophir

Chapter two:

-after arriving Noctis complinet on her tastes and ask about her relationship status
-NEVER ask about her childhood!!!
-once the rover recovered by mutants she will ask for serums(money) for tools. Give her.
-complete companion quest
-after companion quest compliment her about her love of travel

Chapter three:

-DONT ALLOW Amelia to kill Scott during her companion quest
-SAVE game
-speak with her again, agree to meet her in your room in mutant valley. Agree to sleep with her and confess your love.
-LOAD to go for another romance achievement